256 Users and Read Only

I have read other issues about this, and have never seen a solution, people just save it to there computer, then delete the one in sharepoint then save it to sharepoint again.
It is supposed to happen again, once it has been opened 256 times again.

The error message seems to be self-explanatory to me: the file in question is being accessed and edited by 256 users already, so can only be opened in read-only mode until that number decreases. The file in question is hosted on SharePoint, as you have said.

What exactly is the problem? Are you saying that the error message is somehow incorrect?

I just did a google search for , and came up with this link.
https://www.sptechcon.com/west/blog/...ge-limitations

This part seemed most related to your question...

Microsoft recommends that site collections should not:

Contain more than 250,000 sites (supported), which, for the record, is a mind-blowingly large number;
Contain more than:
100 GB of information (relatively small considering the number of sites it can support) in SharePoint 2013; or
1 TB of information in SharePoint Online (default starts at 1 GB so you have to request an increase from your IT administrator);
Have more than 2 million users (supported), which is, again, a huge number (and probably only important to IT since they likely control who users are);
Have more than 5,000 users in a SharePoint group (supported), which is actually somewhat contradictory to the last item; and
Utilize more than 10,000 SharePoint groups.

1 question though - are you saying that you get this msg after the file has been opened 256 times (2, 4, 8, 16, 32....256?) or if 256 users have it open at 1 time?