Does this occur on all workstations?
Check Help-System Information and verify Common Services is installed and active.
Verify the Licenses. Could be the license got deleted.
Does Common Services show on the Sage menu?
Re-install the system manager to re-install common services.

I checked and Common Services is installed and active, licence is good too. And I reinstalled System Manager still the same error message. Maybe something in the tables?

The CSAPP table controls the applications and versions that are installed. Could check that.
Any third party products installed?

Anytime we have seen this error, it has been legitimate. Usually a third party product that was not install.
Generate an RvSpy log and I would be glad to take a look at it.
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Another thought..... we have seen virus checkers stripping dll's from the Sage install. Verify the anti-virus software is not quarantining anything from Sage.