diff --git a/backend/b2/upload.go b/backend/b2/upload.go
index ef0102347..777852b1a 100644
--- a/backend/b2/upload.go
+++ b/backend/b2/upload.go
@@ -417,7 +417,13 @@ func (up *largeUpload) Stream(ctx context.Context, initialUploadBlock *pool.RW)
 		} else {
 			n, err = io.CopyN(rw, up.in, up.chunkSize)
 			if err == io.EOF {
-				fs.Debugf(up.o, "Read less than a full chunk, making this the last one.")
+				if n == 0 {
+					fs.Debugf(up.o, "Not sending empty chunk after EOF - ending.")
+					up.f.putRW(rw)
+					break
+				} else {
+					fs.Debugf(up.o, "Read less than a full chunk %d, making this the last one.", n)
+				}
 				hasMoreParts = false
 			} else if err != nil {
 				// other kinds of errors indicate failure