be careful!, ‘main business spreadsheet’ sounds like valuable data …
a cautious approach to unknown failures should be:
- first! copy all important data to another data medium / check the backup,
- then: check that this data does not contain any errors,
- only then! change anything in the system.
why? depending on the installation and error it might be necessary to search the hard disk for any backups or fragments, this becomes more difficult with every change.
once that is done you may also try to first install a clean copy in a separate directory besides your version in use and try if that helps, in windows use ‘msiexec /a Libre…xxx’ for that,
and - also for further questions - pls. provide some more info about your system and use and change history,