diff --git a/cmd/bucket-replication.go b/cmd/bucket-replication.go
index 82c00f631..979c3924b 100644
--- a/cmd/bucket-replication.go
+++ b/cmd/bucket-replication.go
@@ -869,7 +869,7 @@ func replicateObject(ctx context.Context, ri ReplicateObjectInfo, objectAPI Obje
 			defer cancel()
 		}
 		r := bandwidth.NewMonitoredReader(newCtx, globalBucketMonitor, gr, opts)
-		if objInfo.Multipart {
+		if objInfo.isMultipart() {
 			if err := replicateObjectWithMultipart(ctx, c, dest.Bucket, object,
 				r, objInfo, putOpts); err != nil {
 				replicationStatus = replication.Failed
diff --git a/cmd/encryption-v1.go b/cmd/encryption-v1.go
index e36e918e1..20a22c2cd 100644
--- a/cmd/encryption-v1.go
+++ b/cmd/encryption-v1.go
@@ -68,10 +68,10 @@ const (
 
 )
 
-// isEncryptedMultipart returns true if the current object is
+// isMultipart returns true if the current object is
 // uploaded by the user using multipart mechanism:
 // initiate new multipart, upload part, complete upload
-func (o *ObjectInfo) isEncryptedMultipart() bool {
+func (o *ObjectInfo) isMultipart() bool {
 	if len(o.Parts) == 0 {
 		return false
 	}
@@ -427,7 +427,7 @@ func DecryptBlocksRequestR(inputReader io.Reader, h http.Header, seqNumber uint3
 
 	bucket, object := oi.Bucket, oi.Name
 	// Single part case
-	if !oi.isEncryptedMultipart() {
+	if !oi.isMultipart() {
 		var reader io.Reader
 		var err error
 		if copySource {
@@ -589,7 +589,7 @@ func (o *ObjectInfo) DecryptedSize() (int64, error) {
 	if _, ok := crypto.IsEncrypted(o.UserDefined); !ok {
 		return 0, errors.New("Cannot compute decrypted size of an unencrypted object")
 	}
-	if !o.isEncryptedMultipart() {
+	if !o.isMultipart() {
 		size, err := sio.DecryptedSize(uint64(o.Size))
 		if err != nil {
 			err = errObjectTampered // assign correct error type
@@ -732,7 +732,7 @@ func (o *ObjectInfo) GetDecryptedRange(rs *HTTPRangeSpec) (encOff, encLength, sk
 	// Assemble slice of (decrypted) part sizes in `sizes`
 	var sizes []int64
 	var decObjSize int64 // decrypted total object size
-	if o.isEncryptedMultipart() {
+	if o.isMultipart() {
 		sizes = make([]int64, len(o.Parts))
 		for i, part := range o.Parts {
 			var partSize uint64
diff --git a/cmd/erasure-metadata.go b/cmd/erasure-metadata.go
index c2631ccb6..964530cfd 100644
--- a/cmd/erasure-metadata.go
+++ b/cmd/erasure-metadata.go
@@ -27,8 +27,6 @@ import (
 	"time"
 
 	"github.com/minio/minio/internal/bucket/replication"
-	"github.com/minio/minio/internal/crypto"
-	"github.com/minio/minio/internal/etag"
 	xhttp "github.com/minio/minio/internal/http"
 	"github.com/minio/minio/internal/logger"
 	"github.com/minio/minio/internal/sync/errgroup"
@@ -143,13 +141,6 @@ func (fi FileInfo) ToObjectInfo(bucket, object string) ObjectInfo {
 	// Extract etag from metadata.
 	objInfo.ETag = extractETag(fi.Metadata)
 
-	// Verify if Etag is parseable, if yes
-	// then check if its multipart etag.
-	et, e := etag.Parse(objInfo.ETag)
-	if e == nil {
-		objInfo.Multipart = et.IsMultipart()
-	}
-
 	// Add user tags to the object info
 	tags := fi.Metadata[xhttp.AmzObjectTagging]
 	if len(tags) != 0 {
@@ -176,14 +167,6 @@ func (fi FileInfo) ToObjectInfo(bucket, object string) ObjectInfo {
 	// Tags have also been extracted, we remove that as well.
 	objInfo.UserDefined = cleanMetadata(fi.Metadata)
 
-	// Set multipart for encryption properly if
-	// not set already.
-	if !objInfo.Multipart {
-		if _, ok := crypto.IsEncrypted(objInfo.UserDefined); ok {
-			objInfo.Multipart = crypto.IsMultiPart(objInfo.UserDefined)
-		}
-	}
-
 	// All the parts per object.
 	objInfo.Parts = fi.Parts
 
diff --git a/cmd/erasure-multipart.go b/cmd/erasure-multipart.go
index e591e1997..aeea297ce 100644
--- a/cmd/erasure-multipart.go
+++ b/cmd/erasure-multipart.go
@@ -783,9 +783,6 @@ func (er erasureObjects) CompleteMultipartUpload(ctx context.Context, bucket str
 		return oi, toObjectErr(err, bucket, object, uploadID)
 	}
 
-	// Calculate s3 compatible md5sum for complete multipart.
-	s3MD5 := getCompleteMultipartMD5(parts)
-
 	uploadIDPath := er.getUploadIDDir(bucket, object, uploadID)
 
 	storageDisks := er.getDisks()
@@ -882,9 +879,9 @@ func (er erasureObjects) CompleteMultipartUpload(ctx context.Context, bucket str
 	}
 
 	// Save successfully calculated md5sum.
-	fi.Metadata["etag"] = s3MD5
-	if opts.UserDefined["etag"] != "" { // preserve ETag if set
-		fi.Metadata["etag"] = opts.UserDefined["etag"]
+	fi.Metadata["etag"] = opts.UserDefined["etag"]
+	if fi.Metadata["etag"] == "" {
+		fi.Metadata["etag"] = getCompleteMultipartMD5(parts)
 	}
 
 	// Save the consolidated actual size.
diff --git a/cmd/fs-v1-metadata.go b/cmd/fs-v1-metadata.go
index 60cd5deb2..5db3c2587 100644
--- a/cmd/fs-v1-metadata.go
+++ b/cmd/fs-v1-metadata.go
@@ -29,8 +29,6 @@ import (
 	"time"
 
 	jsoniter "github.com/json-iterator/go"
-	"github.com/minio/minio/internal/crypto"
-	"github.com/minio/minio/internal/etag"
 	xhttp "github.com/minio/minio/internal/http"
 	"github.com/minio/minio/internal/lock"
 	"github.com/minio/minio/internal/logger"
@@ -170,11 +168,6 @@ func (m fsMetaV1) ToObjectInfo(bucket, object string, fi os.FileInfo) ObjectInfo
 
 	objInfo.ETag = extractETag(m.Meta)
 
-	et, e := etag.Parse(objInfo.ETag)
-	if e == nil {
-		objInfo.Multipart = et.IsMultipart()
-	}
-
 	objInfo.ContentType = m.Meta["content-type"]
 	objInfo.ContentEncoding = m.Meta["content-encoding"]
 	if storageClass, ok := m.Meta[xhttp.AmzStorageClass]; ok {
@@ -184,6 +177,7 @@ func (m fsMetaV1) ToObjectInfo(bucket, object string, fi os.FileInfo) ObjectInfo
 	}
 	var (
 		t time.Time
+		e error
 	)
 	if exp, ok := m.Meta["expires"]; ok {
 		if t, e = time.Parse(http.TimeFormat, exp); e == nil {
@@ -200,14 +194,6 @@ func (m fsMetaV1) ToObjectInfo(bucket, object string, fi os.FileInfo) ObjectInfo
 	// Tags have also been extracted, we remove that as well.
 	objInfo.UserDefined = cleanMetadata(m.Meta)
 
-	// Set multipart for encryption properly if
-	// not set already.
-	if !objInfo.Multipart {
-		if _, ok := crypto.IsEncrypted(objInfo.UserDefined); ok {
-			objInfo.Multipart = crypto.IsMultiPart(objInfo.UserDefined)
-		}
-	}
-
 	// All the parts per object.
 	objInfo.Parts = m.Parts
 
diff --git a/cmd/fs-v1-multipart.go b/cmd/fs-v1-multipart.go
index 73382b66e..b3417014a 100644
--- a/cmd/fs-v1-multipart.go
+++ b/cmd/fs-v1-multipart.go
@@ -564,9 +564,6 @@ func (fs *FSObjects) CompleteMultipartUpload(ctx context.Context, bucket string,
 		return oi, toObjectErr(err, bucket, object)
 	}
 
-	// Calculate s3 compatible md5sum for complete multipart.
-	s3MD5 := getCompleteMultipartMD5(parts)
-
 	// ensure that part ETag is canonicalized to strip off extraneous quotes
 	for i := range parts {
 		parts[i].ETag = canonicalizeETag(parts[i].ETag)
@@ -755,7 +752,12 @@ func (fs *FSObjects) CompleteMultipartUpload(ctx context.Context, bucket string,
 	if fsMeta.Meta == nil {
 		fsMeta.Meta = make(map[string]string)
 	}
-	fsMeta.Meta["etag"] = s3MD5
+
+	fsMeta.Meta["etag"] = opts.UserDefined["etag"]
+	if fsMeta.Meta["etag"] == "" {
+		fsMeta.Meta["etag"] = getCompleteMultipartMD5(parts)
+	}
+
 	// Save consolidated actual size.
 	fsMeta.Meta[ReservedMetadataPrefix+"actual-size"] = strconv.FormatInt(objectActualSize, 10)
 	if _, err = fsMeta.WriteTo(metaFile); err != nil {
diff --git a/cmd/object-api-datatypes.go b/cmd/object-api-datatypes.go
index 03779211e..8aef0c8b9 100644
--- a/cmd/object-api-datatypes.go
+++ b/cmd/object-api-datatypes.go
@@ -165,8 +165,6 @@ type ObjectInfo struct {
 
 	Legacy bool // indicates object on disk is in legacy data format
 
-	Multipart bool // indicates if object is multipart object.
-
 	// backendType indicates which backend filled this structure
 	backendType BackendType
 
@@ -187,7 +185,6 @@ func (o ObjectInfo) Clone() (cinfo ObjectInfo) {
 		Size:               o.Size,
 		IsDir:              o.IsDir,
 		ETag:               o.ETag,
-		Multipart:          o.Multipart,
 		InnerETag:          o.InnerETag,
 		VersionID:          o.VersionID,
 		IsLatest:           o.IsLatest,
diff --git a/cmd/object-api-options.go b/cmd/object-api-options.go
index 26cf230fd..7162f0c39 100644
--- a/cmd/object-api-options.go
+++ b/cmd/object-api-options.go
@@ -357,5 +357,6 @@ func completeMultipartOpts(ctx context.Context, r *http.Request, bucket, object
 		}
 	}
 	opts.MTime = mtime
+	opts.UserDefined = make(map[string]string)
 	return opts, nil
 }
diff --git a/cmd/object-api-utils.go b/cmd/object-api-utils.go
index 961be2f7b..0f9ae1a84 100644
--- a/cmd/object-api-utils.go
+++ b/cmd/object-api-utils.go
@@ -290,10 +290,10 @@ func cleanMetadataKeys(metadata map[string]string, keyNames ...string) map[strin
 
 // Extracts etag value from the metadata.
 func extractETag(metadata map[string]string) string {
-	// md5Sum tag is kept for backward compatibility.
-	etag, ok := metadata["md5Sum"]
+	etag, ok := metadata["etag"]
 	if !ok {
-		etag = metadata["etag"]
+		// md5Sum tag is kept for backward compatibility.
+		etag = metadata["md5Sum"]
 	}
 	// Success.
 	return etag
diff --git a/cmd/object-handlers.go b/cmd/object-handlers.go
index d720f1a57..0c7710e3b 100644
--- a/cmd/object-handlers.go
+++ b/cmd/object-handlers.go
@@ -3046,8 +3046,10 @@ func (api objectAPIHandlers) CompleteMultipartUploadHandler(w http.ResponseWrite
 
 	// Complete parts.
 	completeParts := make([]CompletePart, 0, len(complMultipartUpload.Parts))
+	originalCompleteParts := make([]CompletePart, 0, len(complMultipartUpload.Parts))
 	for _, part := range complMultipartUpload.Parts {
 		part.ETag = canonicalizeETag(part.ETag)
+		originalCompleteParts = append(originalCompleteParts, part)
 		if isEncrypted {
 			// ETag is stored in the backend in encrypted form. Validate client sent ETag with
 			// decrypted ETag.
@@ -3063,6 +3065,9 @@ func (api objectAPIHandlers) CompleteMultipartUploadHandler(w http.ResponseWrite
 		completeParts = append(completeParts, part)
 	}
 
+	// Calculate s3 compatible md5sum for complete multipart.
+	s3MD5 := getCompleteMultipartMD5(originalCompleteParts)
+
 	completeMultiPartUpload := objectAPI.CompleteMultipartUpload
 
 	// This code is specifically to handle the requirements for slow
@@ -3104,6 +3109,11 @@ func (api objectAPIHandlers) CompleteMultipartUploadHandler(w http.ResponseWrite
 		return
 	}
 
+	// preserve ETag if set, or set from parts.
+	if _, ok := opts.UserDefined["etag"]; !ok {
+		opts.UserDefined["etag"] = s3MD5
+	}
+
 	w = &whiteSpaceWriter{ResponseWriter: w, Flusher: w.(http.Flusher)}
 	completeDoneCh := sendWhiteSpace(w)
 	objInfo, err := completeMultiPartUpload(ctx, bucket, object, uploadID, completeParts, opts)