why would my OneDrive suddenly be processing over 40,000 changes?

Happening for me too. Notable; it processes way slower than usual, no changes listed in the little menu when clicking on the little icon, no big chances made to files in days.

Adding info that might help someone in the future get to the bottom of what is causing this:

I use "Obsidian.md" for note taking. I use a third party plugin with the program that syncs my "Vault" directly with OneDrive. There is a built in feature in this plugin that warns you when a sync attempt would replace/remove/edit >50% of all files, the goal of the feature being to avoid syncing an accidental deletion of many files at once. For reference, the saving situation includes a local (non-OneDrive) "Vault" folder that updates in real time as you edit while the sync plugin creates a separate folder in your OneDrive that updates when you manually ask to sync your local files to the cloud files.

When I attempted to sync my Obsidian files to OneDrive after both instances of OneDrive trying to process 40,000+ files, Obsidian warned me that 100% of the files I was trying to sync were different than the ones already saved in OneDrive. Now, my files were unchanged (to my eye) when I did allow the sync and I did not have any problems, but such a warning suggests that when OneDrive is "processing" the 40,000+ changes, it actually is processing ""changes.""

I do not know much at all about technology and have no clue what that could mean on the technical side, but because this thread is full of other comments about this I thought it would be smart to add in info that could help the smarter people figure out what's going on.

Edit: In terms of what worked for me when I encountered this problem twice, I had to unlink and relink my desktop from OneDrive and allow it to go through the motions of syncing all files after I relinked the account.

This worked for me and is a really simple fix. Thanks.

I have the same issue, it's been "processing changes" for days now.

I suspect, and this is just a hunch, and I have zero proof, that since MS is pushing AI tools down everyone's throats, this "reindexing" is some kind of AI-analysis during which all files are being "touched" and, as a result, changed (on a metadata level), so now OneDrive has to sync all those changes.

I cannot think of any other reason, maybe except for MS going full vibe coding mode and their codebase have been poisoned by poor quality AI slop.

It's a sad state, I really used to trust MS with this kind of stuff and am a - for now happily - paying customer, but if goes further this route I will have to move my files elsewhere.

I am also having this issue...trying to process > 500,000 files. Nothing has changed on my MacBook Air, so what has changed with Microsoft that is triggering this issue?