We can't do that because the file was deleted or checked out message

I have read through all of the related threads, and tried the suggestions to no avail.<o:p></o:p>

I was previously able to check out documents, then I started receiving this message. Others are also receiving the mesage.  
I am using SharePoint Online, with Office 2013. 

Documents are stored on the cloud. I am opening the document from my SharePoint site. I receive the same message in Visio, Excel, and Word.

As administrator, I would prefer to have the documents checked out prior to update for auditing purposes. Any other
suggestions.<o:p></o:p>

Thank you, in advance, for your help.

Kathryn Mary