我用GHOST8.2精简版出现a source volume could not be locked ,失败了?

我用GHOST8.2精简版出现a source volume could not be locked ,失败了?我用GHOST8.2给C盘做备份到H盘,选了'local','partition','to image',选了’primary',在look in 选了H,起了名字,点save,出现提示：a source volume could not be locked as it is in use by another process.do you wish to attempt to force a dismount on the volume?all open handles to this volume would then be invalid.备份的操作过程就失败了．请问该如何解决