Start by running down the Troubleshooter

Thank you. I'm following this guidance. Would it be the same if I make a copy of the database, erase everything else but the Tables and make this the back end database? Would this be efficient?

While yes you can do it manually like that, I'd be more towards wanting to find and fix the problem then try to make a workaround to something that may be corrupt or have problems that will bite you later. A few possible problems I seen online.

Some of this may be covered in the troubleshooter but just to make sure you have tried.

Restart PC
Unlink tables before splitting if you have any linked tables
Run Compact and Repair
Open each code module and run the compile to check for code errors
The size of your database isn't near the 2GB max is it?

You may also want to be aware that most of the information I found, suggested that there is a corruption problem and to import the items into a new database if these solutions didn't work.

Thank you very much, I'll follow these steps.