diff --git a/pkg/converter/convert.go b/pkg/converter/convert.go
index 571f5f3040..b03b721d2b 100644
--- a/pkg/converter/convert.go
+++ b/pkg/converter/convert.go
@@ -221,11 +221,13 @@ func Convert(ctx context.Context, dest io.Writer, opt ConvertOption) (io.WriteCl
 
 	pr, pw := io.Pipe()
 
+	unpackDone := make(chan bool, 1)
 	go func() {
 		if err := unpackOciTar(ctx, sourceDir, pr); err != nil {
 			pr.CloseWithError(errors.Wrapf(err, "unpack to %s", sourceDir))
 			return
 		}
+		unpackDone <- true
 	}()
 
 	wc := newWriteCloser(pw, func() error {
@@ -233,6 +235,11 @@ func Convert(ctx context.Context, dest io.Writer, opt ConvertOption) (io.WriteCl
 			os.RemoveAll(workDir)
 		}()
 
+		// Because PipeWriter#Close is called does not mean that the PipeReader
+		// has finished reading all the data, and unpack may not be complete yet,
+		// so we need to wait for that here.
+		<-unpackDone
+
 		bootstrapPath := filepath.Join(workDir, "bootstrap")
 		blobPath := filepath.Join(workDir, "blob")
 
diff --git a/pkg/converter/utils.go b/pkg/converter/utils.go
index a571b4a311..8fba62945f 100644
--- a/pkg/converter/utils.go
+++ b/pkg/converter/utils.go
@@ -26,13 +26,16 @@ func (c *writeCloser) Close() error {
 	if c.closed {
 		return nil
 	}
-	if err := c.action(); err != nil {
-		return err
-	}
+
 	if err := c.WriteCloser.Close(); err != nil {
 		return err
 	}
 	c.closed = true
+
+	if err := c.action(); err != nil {
+		return err
+	}
+
 	return nil
 }