This is a Windows 10 Pro PC on a SBS 2008 network. It has been running fine for a couple of years. I mainly use it for developing our MS Access database application. Just last week I noticed that when try and copy the program file over to the network, the copy process stalls part way through. After this happens, the source file is locked and I can no longer open it to make any changes. At that point I have to reboot and the file is unlocked again. I then experimented a little and found that I could not copy any large file >40Mb to any location. I can't even copy these files to a memory stick. Can anyone suggest how I can fix this?