As AnkiWeb is a free service, we need to periodically delete unused account data in order to keep costs down. As mentioned in our terms of service, your data may be deleted if you have not accessed your account or synced in the last 6 months.
Once your deck data has expired, it is not possible for us to recover your data from AnkiWeb, but you may be able to recover it if you have a local copy.
If your AnkiWeb account expires, only the AnkiWeb copy of your data is deleted. Any cards you have stored on your computer, phone or tablet will remain on those devices.
If your account data was deleted due to inactivity, you may still be able to recover that data if you have a copy on your computer or mobile device. You can confirm this by opening Anki or AnkiMobile/AnkiDroid to see if your data is still there. If you had data on your device but accidentally overwrote it in a sync, you may be able to recover it from an automatic backup
If you'd like to start syncing that data with AnkiWeb again, please start by logging in to ankiweb.net using your Anki ID. If you receive a message that no such account exists, you'll need to sign up again first - you can use the same email address as before if you wish.
Once you have a valid AnkiWeb login, you can sync your computer or mobile device, enter your details, and then choose "Upload" to send your data back to AnkiWeb. Please make sure to upload, as choosing download would overwrite your local content with your empty AnkiWeb collection.
Each time you visit ankiweb.net, or use the synchronisation feature in Anki, AnkiMobile or AnkiDroid, your account will automatically be marked as active. The mobile clients do not sync automatically, so simply using them to study will not result in your AnkiWeb account being marked active unless you use the sync button.
If your account has been inactive for 6 months or more, and you used the service for a week or longer, we will send you an email notifying you that deletion is pending. If you'd like to keep your account active, please log in to ankiweb.net and study a card, or sync one of your devices within 30 days.
If you're not planning to study for a while, or if you receive an inactivity notice and don't wish to renew your account immediately, please ensure that you have a copy of your collection on your local computer or mobile device. Your data should already be on your device if you've used Anki's synchronisation feature. If you've only used AnkiWeb before, please install the computer version or a mobile client and sync with AnkiWeb in order to download your data.
When you share a deck, a copy of the deck without scheduling information is made, and that copy along with any add-ons you share are not subject to the usual data expiry.
Please note however that shared decks will expire if they average less than a few downloads a month, so deck sharing is not a backup mechanism.