Hi

I have a user who has been chronically experiencing this problem, he appears to be the only one and it persists regardless of spreadsheet size, and will appear even if excel is the only program open. It occurs at seemingly random times, and will be associated with copy paste (off and on) or sometimes it will just pop up while his spreadsheets are open. I have tried running the fix wizard in programs and features, as well as uninstalling and re-installing Office, neither worked. We have upgraded from 32bit processors to 64 bit and is now reading 12gb of memory. Everything is up to date, software wise, we even gave him a new PC. It is an office PC so is linked to a network. It causes him to have to close all spreadsheets and exit excel to then go back into all the spreadsheets. He doesn't have more than 6-7 open at a time and this will occur, and they are not overly big in size. This is something that has been ongoing for so long, and it feels like we have exhausted all our resources, and can not find anything wrong with the software. We have been advised against 64 bit excel as it could cause issue with Bloomberg and other applications used. However we have upgraded to this just to see if we can rectify the problem, which hasn't helped. We have tried saving each file to the PC instead of opening them from external emails and from downloads and working on them that way, and we still got the error. 

it sounds like the program conflict, since you have re-install and even changed a pc, see the other program cause it.

KR