.doxc was started with an invalid parameter|.ots/.odt does not exist

I have 25 ODF Text Docs in Recent Files. Of those only about (4) will open now. The rest of them when trying to open display: (file name).doxc was started with an invalid parameter OR (file name).odt does not exist. Never had this problem before. It just popped up tonight. These are just regular text files with lots of important info. Under Create if I click Writer Doc/Impress Presentation/Draw Drawing/Math Formula/or Base Database they all open normally. If I click Calc Spreaksheet it displays: [ (file name).ots does not exist ] then I click OK and a new file opens in LibreOffice Calc.
Have I lost all my files? I’ve just upgraded to 6.3.3.2 (x64) Build ID: a64200df03143b798afd1ec74a12ab50359878ed running Win 10 Pro.

Have I lost all my files?

Probably not - but you may have moved them to another location of your disk and the reference in the recent document list is not valid any longer. Hoover your mouse over the thumbnails and you’ll get the location on the disk, where LibreOffice expects the files to be. Check the file in File Explorer and use Open -> File instead of clicking the thumbnails.

Another possibility might be that your user profile is corrupt and you need to reset the user profile (Note: Re-installing LibreOffice in case of a corrupt user profile won’t help).

Thank you very much for taking the time to reply to my question. Oddly, hoovering over a thumbnail I can’t open the file and it says it does not exist in C:. Following the hoovered path, however to C’s location I find the file and can open it. As well, clicking Calc Spreadsheet under Create: This pops up:

C:\Users\Owner\AppData\Roaming\LibreOffice\4\user\template\JSL EXCELTEMPLATE.ots does not exist

When I click OK then a normal Excel sheet opens. For Writer Doc/Impress/Draw/Math/Base there’s no pop up and they all open normally.

Referencing this [ https://bit.ly/2qeTTyY ] I have run Calc Spreadsheet in Safe Mode’s [Restore from backup] [Configure] [Extensions] [Reset to factory settings] [Advanced] with all boxes ticked/unticked in each Safe category. In Safe the Calc Spreadsheet bug is not repeated. I’ve reset my entire user profile. In Restart/Normal the Calc Spreadsheet bug is repeated. Is this a bug for Bugzilla? Kindly advise.

I’m having the same problem in Debian 10 KDE. It SEEMS it has to do with language locale. If there are any accents or different characters in the file name, it does not open the file. Is there a way to fix this?