I just downloaded LibreOffice to my iMac running Catalina to see if it will work for me. I tried creating new documents in Writer and Calc, and I could not save either. The beachball spun for ~20 seconds and then just stopped, no error message or anything. I CAN edit and save an existing document.
Because you can open and save existing files, I guess that you already given LibreOffice full disk access in System Preferences > Security & Privacy
I didn’t know I had to - so I did and now I can Save. Thank you!
Answer accepted 2020-11-29:
Give LibreOffice full disk access in System Preferences > Security & Privacy. This is a security feature of MacOS. Cheers Al
In an Answer @Caudel had written this comment: (Answer deleted)
This solution doesn’t work for me. I added full disk access (see attached figure) but still have trouble saving new files.
I have to copy an existing file, rename it, open it up, erase the old material and add the new content. Then I can save it.
@Caudel this looks like a a MacOS issue. This answer about Illustrator might apply.
That is go to Preferences > General and tick box Use legacy “File New” interface.
The Illustrator answer was on the right track. After clicking on “Use LibreOffice dialogs” in Preferences → General → Open/Save Dialogs, I can now save new files directly from LibreOffice!
The only drawback is having to use the LibreOffice dialogs. At the risk of looking a gift horse in the mouth, the dialogs are pretty archaic in appearance and navigation in the file system is not as easy as in the native versions. I will probably only toggle the setting when needed.