解決問題看這邊 http://forum.synology.com/enu/viewtopic.php?f=49&t=66954
I encountered this error basically when moving files between Shared folders or when deleting whole directories. I will be presented with the following error "The action can't be completed because the file is open in windows explorer". I thought that there was a problem on my network but I was able to get the solution from the internet. This might be useful to noobs like me.
SOLUTION:
1. Run gpedit.msc
2. Navigate to Local Computer Policy->User Configuration->Administrative templates->Windows Components->Windows Explorer
3. Set "Turn off the display of thumbnails and only display icons on network folders" to Enable.
Then, try to test this issue again.
不用重新開機