I have an SMB share on a Mac OS X 10.8.5 server that contains various MS .xlsx documents. This share is accessed from a Win7 Pro machine. When I open certain .xlsx documents I get an error message saying that the file is in use and I can either notify the user, open it in read only, or cancel. If I cancel and then re-open the file it opens fine and I can continue to work as usual. If I then save and close the file, and then open it again later the same day it opens fine. But if I open it again the next day I only sometimes have the same issue, so it's not consistent.
One thing to note is that I had an intern working with me about a month ago and the intern was using my user credentials to access the same share, so were were working on some of the same files (of course not simultaneously). I'm thinking this may be related to the cause of the problem, but I don't know how to fix it.
If anyone has any insight or experienced something similar, help would be much appreciated.