I am getting a rash of this error on just about all of my pc's with win7 pro and office standard 2010. I am running Server 2008 R2 standard. These excel files that are giving me issues are shared on the server. I have removed the Symantec Endpoint client on one client and it made no difference. This client has no antivirus installed and continues to get this error. I have installed unlocker on this same system and unchecked the detail pane within windows explorer. I have not found anything that will stop this issue. Any ideas or help would be appreciated.