Today I got a weird error. I couldn't find many solutions online. Here's my story in case it happens to you:
I searched for a specific card I made a while ago, and couldn't find it. Then I went to its deck and found that 500+ cards were gone, with a message that read something like: "Database appears to be in an inconsistent state". I panicked a little and quickly exported a security backup of my other devices.
The message also recommended to "Tools > Check database", so I did. This created a new deck called "recovery21637826113258" or some long string of numbers i can't remember. The cards in this deck were the 550 cards I had lost previously, and they kept their card info (so I didn't worry about losing progress).
When I exited the deck, I saw all of the cards were programmed for today (500+ cards, oof). But then I checked the "scheduled date" and it was in 1747. So I moved all the cards to their corresponding decks and re-programmed them for the next 2 weeks.
The issue that caused this is, I think, the fact that I built a custom deck and tried to sync it on another device. Then not clearing the deck, and choosing to keep the latter device's sync info. Definitely it was a syncing error. Don't be me, sync your decks periodically.
TL;DR:
- Got a weird corruption error that "erased" 500+ cards
- Did "Tools > Check database" and it created a new deck with my lost cards
- The lost cards were scheduled for 1747 but kept their "anki info"
- I re-scheduled them for the next two weeks to solve this
- The problem came form a syncing error involving a custom deck (most probably)
Edit: typo