Files sharing violation

我用的是win8.1 office 2010, 有一個folder在群組內分享, 但昨天用copy抄左個folder落手指, 帶去另一個電腦做野, 之後在原本的電腦那個folder做excel, 想存檔, 就存唔到.佢彈左個方塊出來 "your file cannot be save, if have to use another file name to save" file sharing violation...?
請問可以點解決?