Uninstalling an older version of zenon leaves the version in startup as unknown

Uninstalling an older version of zenon leaves the version in startup as unknown

Hello,
I've had zenon 10 installed, then installed 11 and uninstalled 10. Ever since my startup tool keeps telling me that it's unable to read the version information for profile [zenon 10], and that it was not found in the old installation directory.
The startup tool shows 2 installed versions, zenon 11 and <Unknown Version>
What should I delete to complete the uninstall of the zenon 10?
Best regards