Error After update

Hello to all !

I recently upgraded from 3.9.3 to 7.0.4. Following the installer i successfully upgraded the database to the version current schema and the whole process finished with no errors.

After the update every time i create an order/invoice/etc i get the following error: Error Duplicate entry ‘facture/ΠΑΡ999-121_invoice-1’ for key ‘uk_ecm_files’
If i delete the the records from the table uk_ecm_files the error stops but later on on other invoices or if i upload a file the error appears again …

How can i fix this ?

The upgrade process should be step by step means version by version.
You need to upgrade to 4.x.x to 5.x.x to 6.x.x to 7.x.x
I did the same mistake upgraded 4.x.x to 7.0.4 some of keys started giving errors with sql format.

Download all the upgrades and start with 1 by 1.
check for error again.
thanks.

P.S. - DON’T FORGET TO TAKE BACK OF YOUR DATABASE