If this sounds like your week
"Word is locked for editing by another user" — but it's just you.
Word refuses to save because the document is "locked," often by a ghost lock left behind after a crash, a sync client, or a preview pane still holding the file. You didn't open it twice. Something else did, and the save-failed loop won't stop.
Where tooling usually breaks
A failed save is the worst time to be guessing.
You risk losing unsaved work while you hunt for the offender. Closing and reopening the app sometimes clears it, sometimes doesn't, and a blind "end task" on the wrong process can take down something you needed.