OneDrive deleting files by having them backed up

[Jason Davies]

Dear Sussex Mac User Group

Someone reported OneDrive deleting files behind his back in this scenario, and I wonder if any of you know why/want the warning.

Scenario: Macbook air 11" is being swapped for another MBA, 13" (henceforth just '11' and '13'). But 11 is running Catalina and 13 has a fresh set-up for Mojave after I erased it for the old owner. My experience of Migration Assistant is that it insists on equivalent OSes. Since Superduper is not yet certified for cloning Catalina drives, I:

• got the new owner to do the most basic set-up of 11 on Mojave;
• installed Catalina;
• ran migration assistant on his Time Machine backup.

So far so good. But he just informed me:

ColleagueX and I discovered this morning that some of the files we are sharing on OneDrive had been erased. Oddly, they were all the files that she had created! We used the 'restore' function on the online version to retrieve everything, so nothing was lost, phew, but the 'restore' function also revealed that I had erased them, and that they had all been erased at about 06:44 on Thursday, when my old laptop was backing up. So it seems to have been caused in some way by the backup.

So somehow creating a (fresh) Time Machine backup led to the eradication of these files, it seems.

Since most people in my dept use OneDrive increasingly because, well, entropy I guess, this is a problem! I avoid it because I distrust MS software (can't think why).

Does anyone have any suggestions for making sure this doesn't happen again?

Cheers,

Jason