I cannot open a spreadsheet I was working on earlier this week… I thought perhaps a file was corrupted so I did a new download… and tried to repair… said it was prevented and to try later…
How are you trying to open it, and what happens when you try? Any error message?
If you are using Windows Defender then you might need to add the new version of LibreOffice to the allowed programs in anti ransomware settings, see Defender Controlled folder access exception for LibreOffice - The Document Foundation Wiki
If you are using a different anti virus then you need to add LibreOffice to that Allowed list
It might be worth clicking Start Menu - Power - Restart first as the recent windows update might be waiting to restart.