This issue is due to having many databases with the same or similar names.
To solve this error:
Do the reinstallation of the UBS system.
Create a new company with a completely different name with the existing database. Do not use a similar name.
For the main PC, you may restore the backup after creating the company with a different name.
For the user PC, you may link it back after creating the company with a different name.
The company name is editable, just ensure to create a company with a different name (Maybe you can put the date of creation).