Cannot create common data folder

On installation on a Windows 10 System, the installer returns the message "Cannot create common data folder." I don't have the foggiest notion how to fix this. Please help.

The file permissions for C:\ProgramData and probably wrong and prevent the account running Opus and/or the account running the installer from creating files there.

It's also worth checking which folder File Explorer goes to if you paste %ProgramData% into its location field. If will normally be C:\ProgramData but could have been moved. Whichever folder it points to should give you read/write access.