We are upgrading all of our XP clients to Window 7 and Office 2010. We have started experiencing frequent problems with users getting "file is in use, locked by "another user"", only when opening the files from Windows Explorer and the file is a docX or xlsX file stored on our IBM I series server (Power7). Opening from a Windows server or local, and it works fine.

The problem does not happen every time. Sometimes its locked, sometimes its not. Open a file 10 times and 5/10 it says locked.

Ive checked with IBM and of course they cant find any reason. Any suggestions?

This sounds similar to a problem we had with some NetApp filers (CMB/CIFS) a very long time ago.

It might be down to the particular SMB/CIFS emulation that your iSeries is using, or, how it's configured.

You may need to dig into that a bit more, and maybe this Linux-related discussion might have some hints?

http://www.experts-exchange.com/OS/Linux/Q_27410397.html

 [opportunistic file locking