Anki reporting that current collection and all backups are corrupt

[Superverbose]

Hi folks, I’m hoping you can help me. I’ve been using Anki for years and years, but recently was out of it for about a week (traveling for work.) When I returned to it this morning, it reported that my database collection was corrupt, and reports the same thing whenever I try to open any of my backups going back to January. Here’s the error output:

Anki 25.02 (038d85b1)  
Python 3.9.18 Qt 6.6.2 PyQt 6.6.1
Platform: Windows-10-10.0.26100

Traceback (most recent call last):
  File "aqt.progress", line 121, in handler
  File "aqt.main", line 231, in on_window_init
  File "aqt.main", line 278, in setupProfileAfterWebviewsLoaded
  File "aqt.main", line 330, in setupProfile
  File "aqt.main", line 545, in loadProfile
  File "anki.scheduler.base", line 59, in day_cutoff
  File "anki.scheduler.base", line 51, in _timing_today
  File "anki._backend_generated", line 730, in sched_timing_today
  File "anki._backend", line 172, in _run_command
anki.errors.DBError: DbError { info: "SqliteFailure(Error { code: DatabaseCorrupt, extended_code: 779 }, Some(\"database disk image is malformed\"))", kind: Other }

I’ve followed every step on the troubleshooting page (which I’d link to but the forum won’t let me – it’s the one that the error message button directs to), with no joy. I’m starting to get a little freaked out – this collection represents over a decade of work for me.

I will note that my database is on Dropbox – I’ve had Anki configured this way from the very beginning with no issues, so I’m not sure what would be causing them today. I keep it there because laptops come and go, and I didn’t want to lose my collection to a disk failure, etc.

One more thought: I took this laptop to a different time zone and back. I see a lot of “timing” and “day” mentions in the error stack. Could that have something to do with the issue?

Any help would be most gratefully received!

[Superverbose]

Just following up on this – thanks to the fact that I have been storing my collection on dropbox, I was able to restore the collection.anki2 file to an earlier version, and the errors disappeared. WHEW!

I’m still not sure what caused the problem in the first place, and it’s super weird and very unsettling that all the backups were reporting as corrupt, but at least I’m back into my collection and flashcarding again. I hope this is helpful to anybody else who has this happen to them.