Writer: Cannot Save Template

tldr; I cannot save a Writer template. Error message is "Cannot save template: "

Long ago I created a template for PDF files that had been converted to .docx. Somehow while tweaking the template formats, I saved it with the contents of a file (rather than no text) and now new documents open with that old file instead of a blank sheet. In trying to fix this, I find I cannot save a Writer template under any circumstances.

I’m running MacOS 10.15.7 on an older MacBook Pro. This is the latest OS my hardware supports. Just upgraded to LibreOffice in the process of troubleshooting. It did not make any difference.

In troubleshooting, I finally arrived at this point:

  • Open LibreOffice
  • Create a new Writer document
    • Create: > Writer Document
  • Immediately try to save as a template under My Templates
    • File > Templates > Save As Template > My Templates > “Trial” > Save
  • I receive the error: “Cannot save template: Trial”
    • OK > Cancel
  • Styles > Manage Styles > Load Styles
    • I see a file “Trial.ott”
    • It seems to load OK. No errors.
  • I change the “Default Paragraph Style” font from “Liberation Serif, Regular, 12” to “Arial, Bold, 14”
  • File > Templates > Save As Template > My Templates > “Trial2” > Save
  • I receive the error: “Cannot save template: Trial2”
  • Restart LibreOffice. Create new blank document. Load styles. I see trial2.ott
  • Load styles from trial2.ott [check “text” and “overwrite”], but the Default Paragraph Style is Liberation Serif. The font change did not save into the template, or was not read from it.
  • Now I try to save the blank document, and receive an error.
    • Error saving the document Untitled 1: Write Error. Error in writing sub-document styles.xml.

I’ve reached the limit of my knowledge. Can anyone help?

You may also want to reset your LibreOffice user profile - but my first guess: see answer of @Hagar_Delest

I tried the answer of @Hagar_Delest, but it did not work. However, I did not know about the Privacy settings prior to this, and LibreOffice was not included in the Full Disk Access list. I added it to access, removed access, added again; three iterations but nothing helped. Also noticed a File and Folder access under Privacy which had LibreOffice selected for Downloads and Documents.
I then restarted in Safe mode and attempted to reset my Profile. Not much feedback but when I created and attempted to save a new file, I got a spinning beach ball then return to cursor with no Save As dialog. Very strange.
I then deleted LibreOffice and my Profile, rebooted, and reinstalled LibreOffice. LO was still enabled for Full Disk Access so I removed access then granted again, per instructions. This time Files and Folders showed LO having Full Disk Access. Running LO, I was able to create and save a file, and open an older file and save as Template.

Could it be that one: Unable to Save or Save As any document even in Safe Mode?