diff --git a/Godeps/Godeps.json b/Godeps/Godeps.json
index bf818444b..f705c6d24 100644
--- a/Godeps/Godeps.json
+++ b/Godeps/Godeps.json
@@ -1,6 +1,6 @@
 {
 	"ImportPath": "github.com/minio/minio",
-	"GoVersion": "go1.4",
+	"GoVersion": "go1.4.2",
 	"Packages": [
 		"./..."
 	],
@@ -37,14 +37,14 @@
 			"ImportPath": "github.com/gorilla/rpc/v2",
 			"Rev": "f6dbf92d77c723632269bf29154cc91f2507693b"
 		},
-		{
-			"ImportPath": "github.com/minio/check",
-			"Rev": "67f8c16c6c27bb03c82e41c2be533ace00035ab4"
-		},
 		{
 			"ImportPath": "github.com/minio/cli",
 			"Comment": "1.2.0-112-g823349c",
 			"Rev": "823349ce91e76834a4af0119d5bbc58fd4d2c6b0"
+		},
+		{
+			"ImportPath": "gopkg.in/check.v1",
+			"Rev": "64131543e7896d5bcc6bd5a76287eb75ea96c673"
 		}
 	]
 }
diff --git a/Godeps/_workspace/src/github.com/minio/check/printer_test.go b/Godeps/_workspace/src/github.com/minio/check/printer_test.go
deleted file mode 100644
index 885ea3342..000000000
--- a/Godeps/_workspace/src/github.com/minio/check/printer_test.go
+++ /dev/null
@@ -1,110 +0,0 @@
-package check_test
-
-import (
-	. "github.com/minio/check"
-)
-
-var _ = Suite(&PrinterS{})
-
-type PrinterS struct{}
-
-func (s *PrinterS) TestCountSuite(c *C) {
-	suitesRun += 1
-}
-
-var printTestFuncLine int
-
-func init() {
-	printTestFuncLine = getMyLine() + 3
-}
-
-func printTestFunc() {
-	println(1)  // Comment1
-	if 2 == 2 { // Comment2
-		println(3) // Comment3
-	}
-	switch 5 {
-	case 6:
-		println(6) // Comment6
-		println(7)
-	}
-	switch interface{}(9).(type) { // Comment9
-	case int:
-		println(10)
-		println(11)
-	}
-	select {
-	case <-(chan bool)(nil):
-		println(14)
-		println(15)
-	default:
-		println(16)
-		println(17)
-	}
-	println(19,
-		20)
-	_ = func() {
-		println(21)
-		println(22)
-	}
-	println(24, func() {
-		println(25)
-	})
-	// Leading comment
-	// with multiple lines.
-	println(29) // Comment29
-}
-
-var printLineTests = []struct {
-	line   int
-	output string
-}{
-	{1, "println(1) // Comment1"},
-	{2, "if 2 == 2 { // Comment2\n    ...\n}"},
-	{3, "println(3) // Comment3"},
-	{5, "switch 5 {\n...\n}"},
-	{6, "case 6:\n    println(6) // Comment6\n    ..."},
-	{7, "println(7)"},
-	{9, "switch interface{}(9).(type) { // Comment9\n...\n}"},
-	{10, "case int:\n    println(10)\n    ..."},
-	{14, "case <-(chan bool)(nil):\n    println(14)\n    ..."},
-	{15, "println(15)"},
-	{16, "default:\n    println(16)\n    ..."},
-	{17, "println(17)"},
-	{19, "println(19,\n    20)"},
-	{20, "println(19,\n    20)"},
-	{21, "_ = func() {\n    println(21)\n    println(22)\n}"},
-	{22, "println(22)"},
-	{24, "println(24, func() {\n    println(25)\n})"},
-	{25, "println(25)"},
-	{26, "println(24, func() {\n    println(25)\n})"},
-	{29, "// Leading comment\n// with multiple lines.\nprintln(29) // Comment29"},
-}
-
-// reformat broke test lines above
-//func (s *PrinterS) TestPrintLine(c *C) {
-//	for _, test := range printLineTests {
-//		output, err := PrintLine("printer_test.go", printTestFuncLine+test.line)
-//		c.Assert(err, IsNil)
-//		c.Assert(output, Equals, test.output)
-//	}
-//}
-
-var indentTests = []struct {
-	in, out string
-}{
-	{"", ""},
-	{"\n", "\n"},
-	{"a", ">>>a"},
-	{"a\n", ">>>a\n"},
-	{"a\nb", ">>>a\n>>>b"},
-	{" ", ">>> "},
-}
-
-func (s *PrinterS) TestIndent(c *C) {
-	for _, test := range indentTests {
-		out := Indent(test.in, ">>>")
-		c.Assert(out, Equals, test.out)
-	}
-
-}
diff --git a/Godeps/_workspace/src/github.com/minio/check/.gitignore b/Godeps/_workspace/src/gopkg.in/check.v1/.gitignore
similarity index 100%
rename from Godeps/_workspace/src/github.com/minio/check/.gitignore
rename to Godeps/_workspace/src/gopkg.in/check.v1/.gitignore
diff --git a/Godeps/_workspace/src/github.com/minio/check/LICENSE b/Godeps/_workspace/src/gopkg.in/check.v1/LICENSE
similarity index 100%
rename from Godeps/_workspace/src/github.com/minio/check/LICENSE
rename to Godeps/_workspace/src/gopkg.in/check.v1/LICENSE
diff --git a/Godeps/_workspace/src/github.com/minio/check/README.md b/Godeps/_workspace/src/gopkg.in/check.v1/README.md
similarity index 78%
rename from Godeps/_workspace/src/github.com/minio/check/README.md
rename to Godeps/_workspace/src/gopkg.in/check.v1/README.md
index 3cf695e5c..0ca9e5726 100644
--- a/Godeps/_workspace/src/github.com/minio/check/README.md
+++ b/Godeps/_workspace/src/gopkg.in/check.v1/README.md
@@ -3,11 +3,11 @@ Instructions
 
 Install the package with:
 
-    go get github.com/minio/check
+    go get gopkg.in/check.v1
     
 Import it with:
 
-    import "github.com/minio/check"
+    import "gopkg.in/check.v1"
 
 and use _check_ as the package name inside the code.
 
diff --git a/Godeps/_workspace/src/github.com/minio/check/TODO b/Godeps/_workspace/src/gopkg.in/check.v1/TODO
similarity index 100%
rename from Godeps/_workspace/src/github.com/minio/check/TODO
rename to Godeps/_workspace/src/gopkg.in/check.v1/TODO
diff --git a/Godeps/_workspace/src/github.com/minio/check/benchmark.go b/Godeps/_workspace/src/gopkg.in/check.v1/benchmark.go
similarity index 100%
rename from Godeps/_workspace/src/github.com/minio/check/benchmark.go
rename to Godeps/_workspace/src/gopkg.in/check.v1/benchmark.go
diff --git a/Godeps/_workspace/src/github.com/minio/check/benchmark_test.go b/Godeps/_workspace/src/gopkg.in/check.v1/benchmark_test.go
similarity index 98%
rename from Godeps/_workspace/src/github.com/minio/check/benchmark_test.go
rename to Godeps/_workspace/src/gopkg.in/check.v1/benchmark_test.go
index b35dbb6f6..4dd827c16 100644
--- a/Godeps/_workspace/src/github.com/minio/check/benchmark_test.go
+++ b/Godeps/_workspace/src/gopkg.in/check.v1/benchmark_test.go
@@ -3,8 +3,8 @@
 package check_test
 
 import (
-	. "github.com/minio/check"
 	"time"
+	. "gopkg.in/check.v1"
 )
 
 var benchmarkS = Suite(&BenchmarkS{})
diff --git a/Godeps/_workspace/src/github.com/minio/check/bootstrap_test.go b/Godeps/_workspace/src/gopkg.in/check.v1/bootstrap_test.go
similarity index 98%
rename from Godeps/_workspace/src/github.com/minio/check/bootstrap_test.go
rename to Godeps/_workspace/src/gopkg.in/check.v1/bootstrap_test.go
index d1d1b4513..e55f327c7 100644
--- a/Godeps/_workspace/src/github.com/minio/check/bootstrap_test.go
+++ b/Godeps/_workspace/src/gopkg.in/check.v1/bootstrap_test.go
@@ -14,7 +14,7 @@ package check_test
 
 import (
 	"fmt"
-	"github.com/minio/check"
+	"gopkg.in/check.v1"
 	"strings"
 )
 
diff --git a/Godeps/_workspace/src/github.com/minio/check/check.go b/Godeps/_workspace/src/gopkg.in/check.v1/check.go
similarity index 100%
rename from Godeps/_workspace/src/github.com/minio/check/check.go
rename to Godeps/_workspace/src/gopkg.in/check.v1/check.go
diff --git a/Godeps/_workspace/src/github.com/minio/check/check_test.go b/Godeps/_workspace/src/gopkg.in/check.v1/check_test.go
similarity index 99%
rename from Godeps/_workspace/src/github.com/minio/check/check_test.go
rename to Godeps/_workspace/src/gopkg.in/check.v1/check_test.go
index 4c087b749..871b32527 100644
--- a/Godeps/_workspace/src/github.com/minio/check/check_test.go
+++ b/Godeps/_workspace/src/gopkg.in/check.v1/check_test.go
@@ -12,7 +12,7 @@ import (
 	"testing"
 	"time"
 
-	"github.com/minio/check"
+	"gopkg.in/check.v1"
 )
 
 // We count the number of suites run at least to get a vague hint that the
diff --git a/Godeps/_workspace/src/github.com/minio/check/checkers.go b/Godeps/_workspace/src/gopkg.in/check.v1/checkers.go
similarity index 100%
rename from Godeps/_workspace/src/github.com/minio/check/checkers.go
rename to Godeps/_workspace/src/gopkg.in/check.v1/checkers.go
diff --git a/Godeps/_workspace/src/github.com/minio/check/checkers_test.go b/Godeps/_workspace/src/gopkg.in/check.v1/checkers_test.go
similarity index 99%
rename from Godeps/_workspace/src/github.com/minio/check/checkers_test.go
rename to Godeps/_workspace/src/gopkg.in/check.v1/checkers_test.go
index 9bdf5c621..5c6974746 100644
--- a/Godeps/_workspace/src/github.com/minio/check/checkers_test.go
+++ b/Godeps/_workspace/src/gopkg.in/check.v1/checkers_test.go
@@ -2,7 +2,7 @@ package check_test
 
 import (
 	"errors"
-	"github.com/minio/check"
+	"gopkg.in/check.v1"
 	"reflect"
 	"runtime"
 )
diff --git a/Godeps/_workspace/src/github.com/minio/check/export_test.go b/Godeps/_workspace/src/gopkg.in/check.v1/export_test.go
similarity index 100%
rename from Godeps/_workspace/src/github.com/minio/check/export_test.go
rename to Godeps/_workspace/src/gopkg.in/check.v1/export_test.go
diff --git a/Godeps/_workspace/src/github.com/minio/check/fixture_test.go b/Godeps/_workspace/src/gopkg.in/check.v1/fixture_test.go
similarity index 99%
rename from Godeps/_workspace/src/github.com/minio/check/fixture_test.go
rename to Godeps/_workspace/src/gopkg.in/check.v1/fixture_test.go
index 2ecad126c..2bff9e163 100644
--- a/Godeps/_workspace/src/github.com/minio/check/fixture_test.go
+++ b/Godeps/_workspace/src/gopkg.in/check.v1/fixture_test.go
@@ -3,7 +3,7 @@
 package check_test
 
 import (
-	. "github.com/minio/check"
+	. "gopkg.in/check.v1"
 )
 
 // -----------------------------------------------------------------------
diff --git a/Godeps/_workspace/src/github.com/minio/check/foundation_test.go b/Godeps/_workspace/src/gopkg.in/check.v1/foundation_test.go
similarity index 99%
rename from Godeps/_workspace/src/github.com/minio/check/foundation_test.go
rename to Godeps/_workspace/src/gopkg.in/check.v1/foundation_test.go
index 0336195f9..8ecf7915f 100644
--- a/Godeps/_workspace/src/github.com/minio/check/foundation_test.go
+++ b/Godeps/_workspace/src/gopkg.in/check.v1/foundation_test.go
@@ -8,7 +8,7 @@ package check_test
 
 import (
 	"fmt"
-	"github.com/minio/check"
+	"gopkg.in/check.v1"
 	"log"
 	"os"
 	"regexp"
diff --git a/Godeps/_workspace/src/github.com/minio/check/helpers.go b/Godeps/_workspace/src/gopkg.in/check.v1/helpers.go
similarity index 100%
rename from Godeps/_workspace/src/github.com/minio/check/helpers.go
rename to Godeps/_workspace/src/gopkg.in/check.v1/helpers.go
diff --git a/Godeps/_workspace/src/github.com/minio/check/helpers_test.go b/Godeps/_workspace/src/gopkg.in/check.v1/helpers_test.go
similarity index 99%
rename from Godeps/_workspace/src/github.com/minio/check/helpers_test.go
rename to Godeps/_workspace/src/gopkg.in/check.v1/helpers_test.go
index 9bb0986a6..4baa656ba 100644
--- a/Godeps/_workspace/src/github.com/minio/check/helpers_test.go
+++ b/Godeps/_workspace/src/gopkg.in/check.v1/helpers_test.go
@@ -4,7 +4,7 @@
 package check_test
 
 import (
-	"github.com/minio/check"
+	"gopkg.in/check.v1"
 	"os"
 	"reflect"
 	"runtime"
diff --git a/Godeps/_workspace/src/github.com/minio/check/printer.go b/Godeps/_workspace/src/gopkg.in/check.v1/printer.go
similarity index 100%
rename from Godeps/_workspace/src/github.com/minio/check/printer.go
rename to Godeps/_workspace/src/gopkg.in/check.v1/printer.go
diff --git a/Godeps/_workspace/src/gopkg.in/check.v1/printer_test.go b/Godeps/_workspace/src/gopkg.in/check.v1/printer_test.go
new file mode 100644
index 000000000..538b2d52e
--- /dev/null
+++ b/Godeps/_workspace/src/gopkg.in/check.v1/printer_test.go
@@ -0,0 +1,104 @@
+package check_test
+
+import (
+    .   "gopkg.in/check.v1"
+)
+
+var _ = Suite(&PrinterS{})
+
+type PrinterS struct{}
+
+func (s *PrinterS) TestCountSuite(c *C) {
+    suitesRun += 1
+}
+
+var printTestFuncLine int
+
+func init() {
+    printTestFuncLine = getMyLine() + 3
+}
+
+func printTestFunc() {
+    println(1)           // Comment1
+    if 2 == 2 {          // Comment2
+        println(3)       // Comment3
+    }
+    switch 5 {
+    case 6: println(6)   // Comment6
+        println(7)
+    }
+    switch interface{}(9).(type) {// Comment9
+    case int: println(10)
+        println(11)
+    }
+    select {
+    case <-(chan bool)(nil): println(14)
+        println(15)
+    default: println(16)
+        println(17)
+    }
+    println(19,
+        20)
+    _ = func() { println(21)
+        println(22)
+    }
+    println(24, func() {
+        println(25)
+    })
+    // Leading comment
+    // with multiple lines.
+    println(29)  // Comment29
+}
+
+var printLineTests = []struct {
+    line   int
+    output string
+}{
+    {1, "println(1) // Comment1"},
+    {2, "if 2 == 2 { // Comment2\n    ...\n}"},
+    {3, "println(3) // Comment3"},
+    {5, "switch 5 {\n...\n}"},
+    {6, "case 6:\n    println(6) // Comment6\n    ..."},
+    {7, "println(7)"},
+    {9, "switch interface{}(9).(type) { // Comment9\n...\n}"},
+    {10, "case int:\n    println(10)\n    ..."},
+    {14, "case <-(chan bool)(nil):\n    println(14)\n    ..."},
+    {15, "println(15)"},
+    {16, "default:\n    println(16)\n    ..."},
+    {17, "println(17)"},
+    {19, "println(19,\n    20)"},
+    {20, "println(19,\n    20)"},
+    {21, "_ = func() {\n    println(21)\n    println(22)\n}"},
+    {22, "println(22)"},
+    {24, "println(24, func() {\n    println(25)\n})"},
+    {25, "println(25)"},
+    {26, "println(24, func() {\n    println(25)\n})"},
+    {29, "// Leading comment\n// with multiple lines.\nprintln(29) // Comment29"},
+}
+
+func (s *PrinterS) TestPrintLine(c *C) {
+    for _, test := range printLineTests {
+        output, err := PrintLine("printer_test.go", printTestFuncLine+test.line)
+        c.Assert(err, IsNil)
+        c.Assert(output, Equals, test.output)
+    }
+}
+
+var indentTests = []struct {
+    in, out string
+}{
+    {"", ""},
+    {"\n", "\n"},
+    {"a", ">>>a"},
+    {"a\n", ">>>a\n"},
+    {"a\nb", ">>>a\n>>>b"},
+    {" ", ">>> "},
+}
+
+func (s *PrinterS) TestIndent(c *C) {
+    for _, test := range indentTests {
+        out := Indent(test.in, ">>>")
+        c.Assert(out, Equals, test.out)
+    }
+
+}
diff --git a/Godeps/_workspace/src/github.com/minio/check/run.go b/Godeps/_workspace/src/gopkg.in/check.v1/run.go
similarity index 100%
rename from Godeps/_workspace/src/github.com/minio/check/run.go
rename to Godeps/_workspace/src/gopkg.in/check.v1/run.go
diff --git a/Godeps/_workspace/src/github.com/minio/check/run_test.go b/Godeps/_workspace/src/gopkg.in/check.v1/run_test.go
similarity index 99%
rename from Godeps/_workspace/src/github.com/minio/check/run_test.go
rename to Godeps/_workspace/src/gopkg.in/check.v1/run_test.go
index abd7c580a..f41fffc3f 100644
--- a/Godeps/_workspace/src/github.com/minio/check/run_test.go
+++ b/Godeps/_workspace/src/gopkg.in/check.v1/run_test.go
@@ -4,7 +4,7 @@ package check_test
 
 import (
 	"errors"
-	. "github.com/minio/check"
+	. "gopkg.in/check.v1"
 	"os"
 	"sync"
 )
@@ -400,7 +400,7 @@ func (s *RunS) TestStreamModeWithMiss(c *C) {
 // -----------------------------------------------------------------------
 // Verify that that the keep work dir request indeed does so.
 
-type WorkDirSuite struct{}
+type WorkDirSuite struct {}
 
 func (s *WorkDirSuite) Test(c *C) {
 	c.MkDir()
@@ -411,7 +411,7 @@ func (s *RunS) TestKeepWorkDir(c *C) {
 	runConf := RunConf{Output: &output, Verbose: true, KeepWorkDir: true}
 	result := Run(&WorkDirSuite{}, &runConf)
 
-	c.Assert(result.String(), Matches, ".*\nWORK="+result.WorkDir)
+	c.Assert(result.String(), Matches, ".*\nWORK=" + result.WorkDir)
 
 	stat, err := os.Stat(result.WorkDir)
 	c.Assert(err, IsNil)
diff --git a/pkg/auth/auth_test.go b/pkg/auth/auth_test.go
index 6ccbbc5f2..4020cb041 100644
--- a/pkg/auth/auth_test.go
+++ b/pkg/auth/auth_test.go
@@ -19,8 +19,8 @@ package auth_test
 import (
 	"testing"
 
-	. "github.com/minio/check"
 	"github.com/minio/minio/pkg/auth"
+	. "gopkg.in/check.v1"
 )
 
 func Test(t *testing.T) { TestingT(t) }
diff --git a/pkg/cpu/cpu_test.go b/pkg/cpu/cpu_test.go
index 3e3f67924..249807e4e 100644
--- a/pkg/cpu/cpu_test.go
+++ b/pkg/cpu/cpu_test.go
@@ -23,8 +23,8 @@ import (
 	"strings"
 	"testing"
 
-	. "github.com/minio/check"
 	"github.com/minio/minio/pkg/cpu"
+	. "gopkg.in/check.v1"
 )
 
 func Test(t *testing.T) { TestingT(t) }
diff --git a/pkg/crypto/md5/md5_test.go b/pkg/crypto/md5/md5_test.go
index c39fdd6c6..d77a7c6d2 100644
--- a/pkg/crypto/md5/md5_test.go
+++ b/pkg/crypto/md5/md5_test.go
@@ -5,8 +5,8 @@ import (
 	"encoding/hex"
 	"testing"
 
-	. "github.com/minio/check"
 	"github.com/minio/minio/pkg/crypto/md5"
+	. "gopkg.in/check.v1"
 )
 
 func Test(t *testing.T) { TestingT(t) }
diff --git a/pkg/donut/bucket.go b/pkg/donut/bucket.go
index 00e3247b4..83e7e1e93 100644
--- a/pkg/donut/bucket.go
+++ b/pkg/donut/bucket.go
@@ -19,7 +19,6 @@ package donut
 import (
 	"bytes"
 	"fmt"
-	"hash"
 	"io"
 	"path/filepath"
 	"sort"
@@ -154,6 +153,13 @@ func (b bucket) ListObjects(prefix, marker, delimiter string, maxkeys int) (List
 	if err != nil {
 		return ListObjectsResults{}, iodine.New(err, nil)
 	}
+	for objectName := range bucketMetadata.Buckets[b.getBucketName()].Multiparts {
+		if strings.HasPrefix(objectName, strings.TrimSpace(prefix)) {
+			if objectName > marker {
+				objects = append(objects, objectName)
+			}
+		}
+	}
 	for objectName := range bucketMetadata.Buckets[b.getBucketName()].BucketObjects {
 		if strings.HasPrefix(objectName, strings.TrimSpace(prefix)) {
 			if objectName > marker {
@@ -171,7 +177,7 @@ func (b bucket) ListObjects(prefix, marker, delimiter string, maxkeys int) (List
 		filteredObjects = HasNoDelimiter(objects, delimiter)
 		prefixes = HasDelimiter(objects, delimiter)
 		prefixes = SplitDelimiter(prefixes, delimiter)
-		prefixes = SortU(prefixes)
+		prefixes = SortUnique(prefixes)
 	}
 	var results []string
 	var commonPrefixes []string
@@ -264,8 +270,9 @@ func (b bucket) WriteObject(objectName string, objectData io.Reader, expectedMD5
 			CleanupWritersOnError(writers)
 			return ObjectMetadata{}, iodine.New(err, nil)
 		}
+		mwriter := io.MultiWriter(sumMD5, sum256, sum512)
 		// write encoded data with k, m and writers
-		chunkCount, totalLength, err := b.writeObjectData(k, m, writers, objectData, sumMD5, sum256, sum512)
+		chunkCount, totalLength, err := b.writeObjectData(k, m, writers, objectData, mwriter)
 		if err != nil {
 			CleanupWritersOnError(writers)
 			return ObjectMetadata{}, iodine.New(err, nil)
@@ -364,11 +371,11 @@ func (b bucket) writeObjectMetadata(objectName string, objMetadata ObjectMetadat
 
 // readObjectMetadata - read object metadata
 func (b bucket) readObjectMetadata(objectName string) (ObjectMetadata, error) {
-	objMetadata := ObjectMetadata{}
 	if objectName == "" {
 		return ObjectMetadata{}, iodine.New(InvalidArgument{}, nil)
 	}
 	var err error
+	objMetadata := ObjectMetadata{}
 	objMetadataReaders, err := b.getObjectReaders(objectName, objectMetadataConfig)
 	if err != nil {
 		return ObjectMetadata{}, iodine.New(err, nil)
@@ -415,7 +422,7 @@ func (b bucket) getDataAndParity(totalWriters int) (k uint8, m uint8, err error)
 }
 
 // writeObjectData -
-func (b bucket) writeObjectData(k, m uint8, writers []io.WriteCloser, objectData io.Reader, sumMD5, sum256, sum512 hash.Hash) (int, int, error) {
+func (b bucket) writeObjectData(k, m uint8, writers []io.WriteCloser, objectData io.Reader, writer io.Writer) (int, int, error) {
 	encoder, err := newEncoder(k, m, "Cauchy")
 	if err != nil {
 		return 0, 0, iodine.New(err, nil)
@@ -432,9 +439,7 @@ func (b bucket) writeObjectData(k, m uint8, writers []io.WriteCloser, objectData
 			return 0, 0, iodine.New(err, nil)
 		}
 
-		sumMD5.Write(chunk.Data)
-		sum256.Write(chunk.Data)
-		sum512.Write(chunk.Data)
+		writer.Write(chunk.Data)
 		for blockIndex, block := range encodedBlocks {
 			errCh := make(chan error, 1)
 			go func(writer io.Writer, reader io.Reader) {
diff --git a/pkg/donut/cache/data/data_test.go b/pkg/donut/cache/data/data_test.go
index 31487d777..b7918f3db 100644
--- a/pkg/donut/cache/data/data_test.go
+++ b/pkg/donut/cache/data/data_test.go
@@ -19,7 +19,7 @@ package data
 import (
 	"testing"
 
-	. "github.com/minio/check"
+	. "gopkg.in/check.v1"
 )
 
 func Test(t *testing.T) { TestingT(t) }
diff --git a/pkg/donut/cache/metadata/metadata_test.go b/pkg/donut/cache/metadata/metadata_test.go
index c12a9a447..ee126b689 100644
--- a/pkg/donut/cache/metadata/metadata_test.go
+++ b/pkg/donut/cache/metadata/metadata_test.go
@@ -19,7 +19,7 @@ package metadata
 import (
 	"testing"
 
-	. "github.com/minio/check"
+	. "gopkg.in/check.v1"
 )
 
 func Test(t *testing.T) { TestingT(t) }
diff --git a/pkg/donut/common.go b/pkg/donut/common.go
index 96fadd4fb..eef8ebb20 100644
--- a/pkg/donut/common.go
+++ b/pkg/donut/common.go
@@ -168,8 +168,8 @@ func SplitDelimiter(objects []string, delim string) []string {
 	return results
 }
 
-// SortU sort a slice in lexical order, removing duplicate elements
-func SortU(objects []string) []string {
+// SortUnique sort a slice in lexical order, removing duplicate elements
+func SortUnique(objects []string) []string {
 	objectMap := make(map[string]string)
 	for _, v := range objects {
 		objectMap[v] = v
diff --git a/pkg/donut/disk/disk_test.go b/pkg/donut/disk/disk_test.go
index 93fc9e87f..8b82f137a 100644
--- a/pkg/donut/disk/disk_test.go
+++ b/pkg/donut/disk/disk_test.go
@@ -22,7 +22,7 @@ import (
 	"path/filepath"
 	"testing"
 
-	. "github.com/minio/check"
+	. "gopkg.in/check.v1"
 )
 
 func TestDisk(t *testing.T) { TestingT(t) }
diff --git a/pkg/donut/donut-v1.go b/pkg/donut/donut-v1.go
index 60da63526..b93a745c6 100644
--- a/pkg/donut/donut-v1.go
+++ b/pkg/donut/donut-v1.go
@@ -191,7 +191,7 @@ func (donut API) putObjectPart(bucket, object, expectedMD5Sum, uploadID string,
 	if err != nil {
 		return PartMetadata{}, iodine.New(err, errParams)
 	}
-	if _, ok := bucketMeta.Buckets[bucket].Multiparts[object+uploadID]; !ok {
+	if _, ok := bucketMeta.Buckets[bucket].Multiparts[object]; !ok {
 		return PartMetadata{}, iodine.New(InvalidUploadID{UploadID: uploadID}, nil)
 	}
 	if _, ok := bucketMeta.Buckets[bucket].BucketObjects[object]; ok {
@@ -208,9 +208,9 @@ func (donut API) putObjectPart(bucket, object, expectedMD5Sum, uploadID string,
 		ETag:         objmetadata.MD5Sum,
 		Size:         objmetadata.Size,
 	}
-	multipartSession := bucketMeta.Buckets[bucket].Multiparts[object+uploadID]
+	multipartSession := bucketMeta.Buckets[bucket].Multiparts[object]
 	multipartSession.Parts[strconv.Itoa(partID)] = partMetadata
-	bucketMeta.Buckets[bucket].Multiparts[object+uploadID] = multipartSession
+	bucketMeta.Buckets[bucket].Multiparts[object] = multipartSession
 	if err := donut.setDonutBucketMetadata(bucketMeta); err != nil {
 		return PartMetadata{}, iodine.New(err, errParams)
 	}
@@ -297,7 +297,7 @@ func (donut API) newMultipartUpload(bucket, object, contentType string) (string,
 		Parts:      make(map[string]PartMetadata),
 		TotalParts: 0,
 	}
-	multiparts[object+uploadID] = multipartSession
+	multiparts[object] = multipartSession
 	bucketMetadata.Multiparts = multiparts
 	allbuckets.Buckets[bucket] = bucketMetadata
 
@@ -326,12 +326,16 @@ func (donut API) listObjectParts(bucket, object string, resources ObjectResource
 	if _, ok := donut.buckets[bucket]; !ok {
 		return ObjectResourcesMetadata{}, iodine.New(BucketNotFound{Bucket: bucket}, errParams)
 	}
-	bucketMetadata, err := donut.getDonutBucketMetadata()
+	allBuckets, err := donut.getDonutBucketMetadata()
 	if err != nil {
 		return ObjectResourcesMetadata{}, iodine.New(err, errParams)
 	}
-	if _, ok := bucketMetadata.Buckets[bucket].Multiparts[object+resources.UploadID]; !ok {
-		return ObjectResourcesMetadata{}, iodine.New(InvalidUploadID{UploadID: resources.UploadID}, nil)
+	bucketMetadata := allBuckets.Buckets[bucket]
+	if _, ok := bucketMetadata.Multiparts[object]; !ok {
+		return ObjectResourcesMetadata{}, iodine.New(InvalidUploadID{UploadID: resources.UploadID}, errParams)
+	}
+	if bucketMetadata.Multiparts[object].UploadID != resources.UploadID {
+		return ObjectResourcesMetadata{}, iodine.New(InvalidUploadID{UploadID: resources.UploadID}, errParams)
 	}
 	objectResourcesMetadata := resources
 	objectResourcesMetadata.Bucket = bucket
@@ -344,7 +348,7 @@ func (donut API) listObjectParts(bucket, object string, resources ObjectResource
 	default:
 		startPartNumber = objectResourcesMetadata.PartNumberMarker
 	}
-	for i := startPartNumber; i <= bucketMetadata.Buckets[bucket].Multiparts[object+resources.UploadID].TotalParts; i++ {
+	for i := startPartNumber; i <= bucketMetadata.Multiparts[object].TotalParts; i++ {
 		if len(parts) > objectResourcesMetadata.MaxParts {
 			sort.Sort(partNumber(parts))
 			objectResourcesMetadata.IsTruncated = true
@@ -352,7 +356,7 @@ func (donut API) listObjectParts(bucket, object string, resources ObjectResource
 			objectResourcesMetadata.NextPartNumberMarker = i
 			return objectResourcesMetadata, nil
 		}
-		part, ok := bucketMetadata.Buckets[bucket].Multiparts[object+resources.UploadID].Parts[strconv.Itoa(i)]
+		part, ok := bucketMetadata.Multiparts[object].Parts[strconv.Itoa(i)]
 		if !ok {
 			return ObjectResourcesMetadata{}, iodine.New(InvalidPart{}, nil)
 		}
@@ -382,11 +386,15 @@ func (donut API) completeMultipartUpload(bucket, object, uploadID string, data i
 	if _, ok := donut.buckets[bucket]; !ok {
 		return ObjectMetadata{}, iodine.New(BucketNotFound{Bucket: bucket}, errParams)
 	}
-	bucketMetadata, err := donut.getDonutBucketMetadata()
+	allBuckets, err := donut.getDonutBucketMetadata()
 	if err != nil {
 		return ObjectMetadata{}, iodine.New(err, errParams)
 	}
-	if _, ok := bucketMetadata.Buckets[bucket].Multiparts[object+uploadID]; !ok {
+	bucketMetadata := allBuckets.Buckets[bucket]
+	if _, ok := bucketMetadata.Multiparts[object]; !ok {
+		return ObjectMetadata{}, iodine.New(InvalidUploadID{UploadID: uploadID}, errParams)
+	}
+	if bucketMetadata.Multiparts[object].UploadID != uploadID {
 		return ObjectMetadata{}, iodine.New(InvalidUploadID{UploadID: uploadID}, errParams)
 	}
 	partBytes, err := ioutil.ReadAll(data)
@@ -409,10 +417,15 @@ func (donut API) completeMultipartUpload(bucket, object, uploadID string, data i
 	if !sort.IsSorted(completedParts(parts.Part)) {
 		return ObjectMetadata{}, iodine.New(InvalidPartOrder{}, errParams)
 	}
+	for _, part := range parts.Part {
+		if part.ETag != bucketMetadata.Multiparts[object].Parts[strconv.Itoa(part.PartNumber)].ETag {
+			return ObjectMetadata{}, iodine.New(InvalidPart{}, errParams)
+		}
+	}
 	var finalETagBytes []byte
 	var finalSize int64
-	totalParts := strconv.Itoa(bucketMetadata.Buckets[bucket].Multiparts[object+uploadID].TotalParts)
-	for _, part := range bucketMetadata.Buckets[bucket].Multiparts[object+uploadID].Parts {
+	totalParts := strconv.Itoa(bucketMetadata.Multiparts[object].TotalParts)
+	for _, part := range bucketMetadata.Multiparts[object].Parts {
 		partETagBytes, err := hex.DecodeString(part.ETag)
 		if err != nil {
 			return ObjectMetadata{}, iodine.New(err, errParams)
@@ -426,7 +439,7 @@ func (donut API) completeMultipartUpload(bucket, object, uploadID string, data i
 	objMetadata.Object = object
 	objMetadata.Bucket = bucket
 	objMetadata.Size = finalSize
-	objMetadata.Created = bucketMetadata.Buckets[bucket].Multiparts[object+uploadID].Parts[totalParts].LastModified
+	objMetadata.Created = bucketMetadata.Multiparts[object].Parts[totalParts].LastModified
 	return objMetadata, nil
 }
 
@@ -446,7 +459,6 @@ func (donut API) listMultipartUploads(bucket string, resources BucketMultipartRe
 		return BucketMultipartResourcesMetadata{}, iodine.New(err, errParams)
 	}
 	bucketMetadata := allbuckets.Buckets[bucket]
-
 	var uploads []*UploadMetadata
 	for key, session := range bucketMetadata.Multiparts {
 		if strings.HasPrefix(key, resources.Prefix) {
@@ -510,7 +522,13 @@ func (donut API) abortMultipartUpload(bucket, object, uploadID string) error {
 		return iodine.New(err, errParams)
 	}
 	bucketMetadata := allbuckets.Buckets[bucket]
-	delete(bucketMetadata.Multiparts, object+uploadID)
+	if _, ok := bucketMetadata.Multiparts[object]; !ok {
+		return iodine.New(InvalidUploadID{UploadID: uploadID}, errParams)
+	}
+	if bucketMetadata.Multiparts[object].UploadID != uploadID {
+		return iodine.New(InvalidUploadID{UploadID: uploadID}, errParams)
+	}
+	delete(bucketMetadata.Multiparts, object)
 
 	allbuckets.Buckets[bucket] = bucketMetadata
 	if err := donut.setDonutBucketMetadata(allbuckets); err != nil {
diff --git a/pkg/donut/donut-v1_test.go b/pkg/donut/donut-v1_test.go
index 80fe565e3..518c8786b 100644
--- a/pkg/donut/donut-v1_test.go
+++ b/pkg/donut/donut-v1_test.go
@@ -27,7 +27,7 @@ import (
 	"strconv"
 	"testing"
 
-	. "github.com/minio/check"
+	. "gopkg.in/check.v1"
 )
 
 func TestDonut(t *testing.T) { TestingT(t) }
diff --git a/pkg/donut/donut-v2.go b/pkg/donut/donut-v2.go
index 7f65d3ab2..c0a77afaf 100644
--- a/pkg/donut/donut-v2.go
+++ b/pkg/donut/donut-v2.go
@@ -579,7 +579,7 @@ func (donut API) ListObjects(bucket string, resources BucketResourcesMetadata, s
 		filteredKeys = HasNoDelimiter(keys, resources.Delimiter)
 		prefixes = HasDelimiter(keys, resources.Delimiter)
 		prefixes = SplitDelimiter(prefixes, resources.Delimiter)
-		prefixes = SortU(prefixes)
+		prefixes = SortUnique(prefixes)
 	}
 	for _, commonPrefix := range prefixes {
 		resources.CommonPrefixes = append(resources.CommonPrefixes, resources.Prefix+commonPrefix)
diff --git a/pkg/donut/donut-v2_test.go b/pkg/donut/donut-v2_test.go
index 5c835de0d..825fb9125 100644
--- a/pkg/donut/donut-v2_test.go
+++ b/pkg/donut/donut-v2_test.go
@@ -26,7 +26,7 @@ import (
 	"path/filepath"
 	"testing"
 
-	. "github.com/minio/check"
+	. "gopkg.in/check.v1"
 )
 
 func TestCache(t *testing.T) { TestingT(t) }
diff --git a/pkg/donut/split/split_test.go b/pkg/donut/split/split_test.go
index 94413a988..d86f840af 100644
--- a/pkg/donut/split/split_test.go
+++ b/pkg/donut/split/split_test.go
@@ -24,8 +24,8 @@ import (
 	"strconv"
 	"testing"
 
-	. "github.com/minio/check"
 	"github.com/minio/minio/pkg/donut/split"
+	. "gopkg.in/check.v1"
 )
 
 type MySuite struct{}
diff --git a/pkg/erasure/cauchy_test.go b/pkg/erasure/cauchy_test.go
index 0c783276f..37f28c74c 100644
--- a/pkg/erasure/cauchy_test.go
+++ b/pkg/erasure/cauchy_test.go
@@ -20,7 +20,7 @@ import (
 	"bytes"
 	"testing"
 
-	. "github.com/minio/check"
+	. "gopkg.in/check.v1"
 )
 
 type MySuite struct{}
diff --git a/pkg/erasure/vandermonde_test.go b/pkg/erasure/vandermonde_test.go
index c126bdfd9..490830557 100644
--- a/pkg/erasure/vandermonde_test.go
+++ b/pkg/erasure/vandermonde_test.go
@@ -19,7 +19,7 @@ package erasure
 import (
 	"bytes"
 
-	. "github.com/minio/check"
+	. "gopkg.in/check.v1"
 )
 
 func corruptChunks(chunks [][]byte, errorIndex []int) [][]byte {
diff --git a/pkg/quick/quick_test.go b/pkg/quick/quick_test.go
index 3140626f5..84af748d8 100644
--- a/pkg/quick/quick_test.go
+++ b/pkg/quick/quick_test.go
@@ -22,7 +22,7 @@ import (
 	"os"
 	"testing"
 
-	. "github.com/minio/check"
+	. "gopkg.in/check.v1"
 )
 
 func Test(t *testing.T) { TestingT(t) }
diff --git a/pkg/server/api_donut_cache_test.go b/pkg/server/api_donut_cache_test.go
index a7ec5f4f9..190ddd7ea 100644
--- a/pkg/server/api_donut_cache_test.go
+++ b/pkg/server/api_donut_cache_test.go
@@ -28,9 +28,9 @@ import (
 	"net/http"
 	"net/http/httptest"
 
-	. "github.com/minio/check"
 	"github.com/minio/minio/pkg/donut"
 	"github.com/minio/minio/pkg/server/api"
+	. "gopkg.in/check.v1"
 )
 
 func TestAPIDonutCache(t *testing.T) { TestingT(t) }
diff --git a/pkg/server/api_donut_test.go b/pkg/server/api_donut_test.go
index becf287c9..bdb141258 100644
--- a/pkg/server/api_donut_test.go
+++ b/pkg/server/api_donut_test.go
@@ -29,9 +29,9 @@ import (
 	"net/http"
 	"net/http/httptest"
 
-	. "github.com/minio/check"
 	"github.com/minio/minio/pkg/donut"
 	"github.com/minio/minio/pkg/server/api"
+	. "gopkg.in/check.v1"
 )
 
 func TestAPIDonut(t *testing.T) { TestingT(t) }
diff --git a/pkg/server/api_signature_v4_test.go b/pkg/server/api_signature_v4_test.go
index bf25530dc..1ebb54f19 100644
--- a/pkg/server/api_signature_v4_test.go
+++ b/pkg/server/api_signature_v4_test.go
@@ -29,10 +29,10 @@ import (
 	"net/http"
 	"net/http/httptest"
 
-	. "github.com/minio/check"
 	"github.com/minio/minio/pkg/auth"
 	"github.com/minio/minio/pkg/donut"
 	"github.com/minio/minio/pkg/server/api"
+	. "gopkg.in/check.v1"
 )
 
 func TestAPISignatureV4(t *testing.T) { TestingT(t) }
diff --git a/pkg/server/minhttp/net_test.go b/pkg/server/minhttp/net_test.go
index de32afd81..9abed21c7 100644
--- a/pkg/server/minhttp/net_test.go
+++ b/pkg/server/minhttp/net_test.go
@@ -21,8 +21,8 @@ import (
 	"regexp"
 	"testing"
 
-	. "github.com/minio/check"
 	"github.com/minio/minio/pkg/iodine"
+	. "gopkg.in/check.v1"
 )
 
 func Test(t *testing.T) { TestingT(t) }
diff --git a/pkg/server/rpc_test.go b/pkg/server/rpc_test.go
index a7f6dd583..0dd8dc0e9 100644
--- a/pkg/server/rpc_test.go
+++ b/pkg/server/rpc_test.go
@@ -22,9 +22,9 @@ import (
 	"testing"
 
 	jsonrpc "github.com/gorilla/rpc/v2/json"
-	. "github.com/minio/check"
 	"github.com/minio/minio/pkg/controller"
 	"github.com/minio/minio/pkg/server/rpc"
+	. "gopkg.in/check.v1"
 )
 
 func TestRPC(t *testing.T) { TestingT(t) }
diff --git a/pkg/utils/atomic/atomic_test.go b/pkg/utils/atomic/atomic_test.go
index 31871b75c..69f045fed 100644
--- a/pkg/utils/atomic/atomic_test.go
+++ b/pkg/utils/atomic/atomic_test.go
@@ -22,7 +22,7 @@ import (
 	"path/filepath"
 	"testing"
 
-	. "github.com/minio/check"
+	. "gopkg.in/check.v1"
 )
 
 func Test(t *testing.T) { TestingT(t) }