I got an issue from one of my users, where he would get the following message whenever he opened a particular excel file stored in a document library.
The workbook is currently open by 256 users. A maximum of 256 users can have a shared workbook open at the same time. The workbook will be opened read-only. You can try again when one or more users have closed the workbook.
I would receive the same error when opening the workbook myself. According to the user, this is a relatively obscure book that shouldn't be being used by that many people. The only interesting thing I noticed about the workbook is that it had over 370 versions associated with it.
Unfortunately, the user "resolved" the issue by deleting the workbook and adding it back again. However, if I could present a possible answer why this occurred, it would be appreciated.
Anyone have any thoughts? Or, if it's actually a 256 user limit, anyone know how I can figure out who currently has the workbook open?