Been having this problem , thought the latest update might sort it but no.
When I add Halion as a instrument track this message appears.
""VST Sound Library "Halion Sonic Electric Piano 200 A01 " Not Found.
Followed by where the file should be ,but its not there.
Your asked if you want to locate the file,but you can see its missing.
If you installed the trial for the full version of Halion or Halion Sonic, or Cubase Pro, you should uninstall them.
The file you’re referring to is likely FCP_SMT_052_HS_El_Piano_200A_01.vstsound . This is a deep sampled Wurlitzer electric piano that’s only included with Cubase Artist or higher, and the full versions of Halion and Halion Sonic.
Yep thats the file.
That explains it.