Had an issue with my accountants using shared workbooks in Office 2010 where the hidden cells created by one user were not hidden when another user opened. I scoured the internet for a solution and found plenty of other people having the problem but didn't really see any solutions. Saw a few things about macros, but none of the workbooks I was troubleshooting had macros in them. I stumbled upon a fix that actually worked for me and thought I'd share it for anyone else that ran into the same problem I had finding a solution.
Within the shared workbook, click in the upper left corner to highlight all cells. Right-click on any of the highlighted cells and select Format Cells, go to the Protection tab and check Hidden, Click OK, save the document, make your changes and save the document again. Tested in multiple scenarios with different users and was able to replicate the results each time in my environment. Hope that helps someone out.