Weird issue with protections

Sounds like user error.

I don't have Excel 2013 but more recent versions of Excel seem more aware of the source of a workbook and try to prevent inadvertent enabling of malware.

They may simply have downloaded the workbook and not followed instructions.

That said, it's entirely guesswork, as I don't have Excel 2013 and I'm not a frequent user of 2010 ... and I don't download spreadsheets from a SharePoint site.

Regards, TMS

Some thoughts on your problem:

If these workbooks have macros in them, I bet that the users are not saving first before trying to edit, even though they say they save first. I have version 2010 and I download both from here and another site that I trust. The workbooks with macros can cause all kinds of strange problems for me (like being able to select cells but not enter data or click on Ribbon Tabs and not be able to select a command....strange stuff) if I don't save to my local hard drive first. After saving and re-opening, all is well. For me, because I know this is a possibility, it is User Error.

I also run Windows 7 and I think that I may have found a bug that may be related to this. If in Windows Explorer the Show the Preview Pane is activated editing problems can occur even with files that I have created. Close the Preview Pane and the problems disappear. It is also more prevalent if directly accessing a file on OneDrive. If Excel just froze that would be one thing but it is the loss of functionality of different things.