I have been editing my-file.ods almost daily using LibreOffice. Today it hanged at one point. I had to reboot the laptop. Now the file cannot be edited. When it is opened for editing, a warning is issues: Document file is locked for editing by unknown user.

If I open the file for editing despite the stated hiccup and edit it and then try to save it, I am prompted to save it under another name. But I don't want to change the name.