diff --git a/crypt/cipher.go b/crypt/cipher.go
index 87747a553..9ce04e9e1 100644
--- a/crypt/cipher.go
+++ b/crypt/cipher.go
@@ -604,9 +604,20 @@ func (fh *decrypter) Seek(offset int64, whence int) (int64, error) {
 		return 0, fh.err
 	}
 
-	// Can we seek it directly?
+	// blocks we need to seek, plus bytes we need to discard
+	blocks, discard := offset/blockDataSize, offset%blockDataSize
+
+	// Offset in underlying stream we need to seek
+	underlyingOffset := int64(fileHeaderSize) + blocks*(blockHeaderSize+blockDataSize)
+
+	// Move the nonce on the correct number of blocks from the start
+	fh.nonce = fh.initialNonce
+	fh.nonce.add(uint64(blocks))
+
+	// Can we seek underlying stream directly?
 	if do, ok := fh.rc.(io.Seeker); ok {
-		_, err := do.Seek(offset, 0)
+		// Seek underlying stream directly
+		_, err := do.Seek(underlyingOffset, 0)
 		if err != nil {
 			return 0, fh.finish(err)
 		}
@@ -615,16 +626,6 @@ func (fh *decrypter) Seek(offset int64, whence int) (int64, error) {
 		_ = fh.rc.Close() // close underlying file
 		fh.rc = nil
 
-		// blocks we need to seek, plus bytes we need to discard
-		blocks, discard := offset/blockDataSize, offset%blockDataSize
-
-		// Offset in underlying stream we need to seek
-		underlyingOffset := int64(fileHeaderSize) + blocks*(blockHeaderSize+blockDataSize)
-
-		// Move the nonce on the correct number of blocks from the start
-		fh.nonce = fh.initialNonce
-		fh.nonce.add(uint64(blocks))
-
 		// Re-open the underlying object with the offset given
 		rc, err := fh.open(underlyingOffset)
 		if err != nil {
@@ -633,12 +634,16 @@ func (fh *decrypter) Seek(offset int64, whence int) (int64, error) {
 
 		// Set the file handle
 		fh.rc = rc
+	}
 
-		// Discard excess bytes
-		_, err = io.CopyN(ioutil.Discard, fh, discard)
-		if err != nil {
-			return 0, fh.finish(err)
-		}
+	// Empty the buffer
+	fh.bufIndex = 0
+	fh.bufSize = 0
+
+	// Discard excess bytes
+	_, err := io.CopyN(ioutil.Discard, fh, discard)
+	if err != nil {
+		return 0, fh.finish(err)
 	}
 
 	return offset, nil
diff --git a/crypt/cipher_test.go b/crypt/cipher_test.go
index 384b83155..5bacdcdcd 100644
--- a/crypt/cipher_test.go
+++ b/crypt/cipher_test.go
@@ -881,15 +881,26 @@ func TestNewDecrypterSeek(t *testing.T) {
 		return ioutil.NopCloser(bytes.NewBuffer(ciphertext[int(underlyingOffset):])), nil
 	}
 
+	inBlock := make([]byte, 1024)
+
+	// Check the seek worked by reading a block and checking it
+	// against what it should be
+	check := func(rc ReadSeekCloser, offset int) {
+		n, err := io.ReadFull(rc, inBlock)
+		if err != nil && err != io.EOF && err != io.ErrUnexpectedEOF {
+			require.NoError(t, err)
+		}
+		seekedDecrypted := inBlock[:n]
+
+		require.Equal(t, plaintext[offset:offset+n], seekedDecrypted)
+	}
+
 	// Now try decoding it with a open/seek
 	for _, offset := range trials {
 		rc, err := c.DecryptDataSeek(open, int64(offset))
 		assert.NoError(t, err)
 
-		seekedDecrypted, err := ioutil.ReadAll(rc)
-		assert.NoError(t, err)
-
-		assert.Equal(t, plaintext[offset:], seekedDecrypted)
+		check(rc, offset)
 	}
 
 	// Now try decoding it with a single open and lots of seeks
@@ -898,10 +909,7 @@ func TestNewDecrypterSeek(t *testing.T) {
 		_, err := rc.Seek(int64(offset), 0)
 		assert.NoError(t, err)
 
-		seekedDecrypted, err := ioutil.ReadAll(rc)
-		assert.NoError(t, err)
-
-		assert.Equal(t, plaintext[offset:], seekedDecrypted)
+		check(rc, offset)
 	}
 }