Comment by TheOtherHobbes

I had a similar issue. I ended my O365 subscription. Outlook kept complaining I had exceeded my free storage, which surprised me because I've never used OneDrive for anything, and my email storage was well under the limit.

I deleted a ton of useless emails anyway, but that didn't fix the problem. Somehow I had more than 25 gigs of space being used on a cloud system I'd never used, tied to an email account which supposedly needed less than 500 Mb of storage.

Eventually after a lot of searching I discovered the magic page that gave me direct access to OneDrive's actual storage - which was not, somehow, the page that gave access to the files.

OneDrive was storing a lot of attachments, and deleting emails and clearing the trash didn't delete them.

Or something like that. Whatever the magic words were, I did eventually find them and fix the problem.

But it took a while, I had to resubscribe for free for a month to make it happen, there was a lot of confusing side information online suggesting I should open a ticket (good luck with that on a consumer account) and generally it Just Didn't Work.

I can imagine people resubscribing for another year just to make it all go away.

This has been my lifelong experience of Microsoft - shockingly poor, contemptuous, or downright stupid interface design, Kafka-esque indifference to the user experience, and constant unwanted friction and complication, around a suite of core consumer products that are mediocre to start with.