Thanks Karl, I suppose it is this, but I updated my Office 365 today and still the error occurs. Not only does it say the file is open and not allow me to compact and repair, but now I get another message saying it will open my file in only share mode as it is already open elsewhere. I cant understand how to solve this. Mine is a standalone computer with no other networked computer or sharing of any kind whatsoever. Even after going to client in account and ensuring that the file is not marked as shared it still does the same thing. And I know it is an error from the applications end as even new database files that I create now just for checking have the same problems. I hope somebody from Microsoft is also reading this. I even uninstalled and reinstalled Office 365 yesterday.
Ripal