diff --git a/backend/dropbox/dropbox.go b/backend/dropbox/dropbox.go
index bb2f62449..11a3360ac 100644
--- a/backend/dropbox/dropbox.go
+++ b/backend/dropbox/dropbox.go
@@ -2051,7 +2051,12 @@ func (o *Object) uploadChunked(ctx context.Context, in0 io.Reader, commitInfo *f
 		SessionId: res.SessionId,
 		Offset:    0,
 	}
-	appendArg := files.UploadSessionAppendArg{Cursor: &cursor}
+	appendArg := files.UploadSessionAppendArg{
+		Cursor: &cursor,
+		// A known-size upload which fits in a single chunk can close the
+		// session with its only append, saving an empty append request
+		Close: size >= 0 && size <= chunkSize,
+	}
 	for currentChunk := 1; ; currentChunk++ {
 		cursor.Offset = in.BytesRead()