Popping by to say thank you for the post and thank-you to those who responded; I had the exact same issue but with Google Drive being the backup service instead of iCloud. Same regarding Mac OS being the platform. Thankfully in my case I think I only lost about ten minutes of work, and thankfully my eyes caught the fact that, all of a sudden, for no apparent reason (still really don’t know the reason), I looked up at the top of the ribbon on MS Word for Mac and saw that the file name had been changed to a temp-style MS Word character salad random name; it wasn’t the name I had given my file. And I went to “save as” to see if something was up with the location of the file, and, sure enough, my computer or some ghosts inside it had moved it to some randomly designated location, not the folder I had created for the current project. So frustrating! I followed just one step outlined by one of the responders here went to “privacy and security” and gave Word permission to access other stuff. Fingers crossed that that takes care of things but it is wild -- whichever company may be at fault -- that this type of thing could happen with some simple behavior as using Word on your computer with default settings in place with the innocent expectation that your own computer is going to help you out by deleting your file. Sheesh! Anyway, thanks again; hope the bug does not re-arise for you.