Today I opened a document where I had to make a few edits and LibreOffice decided to tell me:
Readonly content cannot be changed.
No modifications will be accepted.
There is a screenshot of that message:
The error may be justified, I do not know, but apparently not too many people know how to unlock a document. I found pages and pages that tell people to check the read/write protection of the file, as if a read-only file on disk could not be updated in the editor... (yes! you cannot write it back, but you can edit it and do a Save As ...)
One person, though, had the correct answer to ...