This occurs because of a license limitation that restricts usage to only one user. Suppose an additional concurrent user license is activated. In that case, users should be able to open the same data on two different computers or allow two people to access the same data simultaneously. To rectify it:
Ensure all PCs (Main & Client) have the latest Windows updates installed.
Ensure the UBS software is updated to the latest version.
Ensure all databases on the main PC are mapped to the C: drive.
Do not mix database mappings (e.g., some on C: drive and others on an external hard drive), as this may cause file corruption and prevent the system from reading data properly.
Please close all other tabs or instances of UBS that are currently open.
Open only once for the data.