Managing Files and Your Collection

Checking Your Collection

It is a good idea to occasionally check your collection file for problems. You can do this via the Tools>Check Database menu item. Checking the database ensures the file has not been corrupted, rebuilds some internal structures, and optimizes the file.

When you check the database, your tag list is also rebuilt. When you delete individual decks or cards, Anki does not update the list of used tags, as it's inefficient to do so. If you want to clear old tags out from the list that are no longer in use, checking your database is the way to do it.

Please note that Anki will automatically optimize your collection once every 2 weeks. This optimization ensures the collection performs well, but it does not check for errors or rebuild the tag list when automatically optimizing.

File Locations

On Windows, the latest Anki versions store your Anki files in your appdata folder. You can access it by opening the file manager, and typing %APPDATA%\Anki2 in the location field. Older versions of Anki stored your Anki files in a folder called Anki in your Documents folder.

On Mac computers, recent Anki versions store all their files in the ~/Library/Application Support/Anki2 folder. The Library folder is hidden by default, but can be revealed in Finder by holding down the option key while clicking on the Go menu. If you're on an older Anki version, your Anki files will be in your Documents/Anki folder.

On Linux, recent Anki versions store your data in ~/.local/share/Anki2, or $XDG_DATA_HOME/Anki2 if you have set a custom data path. Older versions of Anki stored your files in ~/Documents/Anki or ~/Anki.

Within the Anki folder, the program-level and profile-level preferences are stored in a file called prefs.db.

There is also a separate folder for each profile. The folder contains:

  • Your notes, decks, cards and so on in a file called collection.anki2

  • Your audio and images in a folder

  • A backups folder

  • Some system files

You should never copy or move your collection while Anki is open. Doing so could cause your collection to become corrupt. Please do not move or modify the other files in the folder either.

Startup Options

If you have made a destructive change on one computer and have an undamaged copy on another computer, you may wish to start Anki without syncing in order to use the full sync option without first downloading the changes. Similarly, if you are experiencing problems with Anki, you might want to (or might be instructed to) disable add-ons temporarily to see if one might be causing the problem. You can do both of these things by holding down the Shift key while starting Anki.

It is possible to specify a custom folder location during startup. This is an advanced feature that is primarily intended to be used with portable installations, and we recommend you use the default location in most circumstances.

The syntax to specify an alternate folder is as follows:

anki -b /path/to/anki/folder
  • If you have multiple profiles, you can pass -p <name> to load a specific profile.

  • If you pass -p some-fake-name, Anki will show the profile screen on startup. If no profile is provided, the last-used profile is loaded.

  • To change the interface language, use -l <iso 639-1 language code>, such as "-l ja" for Japanese.

If you always want to use a custom folder location, you can modify your shortcut to Anki. On Windows, right-click on the shortcut, choose Properties, select the Shortcut tab, and add "-b \path\to\data\folder" after the path to the program, which should leave you with something like

"C:\Program Files\Anki\anki.exe" -b "C:\AnkiDataFolder"

You can also use this technique with the -l option to easily use Anki in different languages.

On Windows, you should use a backslash (\) not a forward slash (/).

On a Mac there is no easy way to alter the behaviour when clicking on the Anki icon, but it is possible to start Anki with a custom base folder from a terminal:

open /Applications/ --args -b ~/myankifolder

Alternatively, you can define the environment variable "ANKI_BASE". On Windows, you can define the environment variable with:

set "ANKI_BASE=C:/path/to/AnkiDataFolder"

On Linux and macOS, you can use:

export ANKI_BASE="/path/to/AnkiDataFolder"

DropBox and File Syncing

We do not recommend you sync your Anki folder directly with a third-party synchronization service, as it can lead to database corruption when files are synced while in use.

If you just want to synchronize your media, you can link external folders into services like DropBox. Please see DropboxWiki: Sync Folders Outside Dropbox ( for more info.

If you wish to keep your collection in sync as well, it is strongly recommended that you create a script that copies your files from your synced folder to a local folder, launches Anki, and then copies the files back when Anki is closed. This will ensure that the files are never synchronized while they are open.

Network Filesystems

We strongly recommend you have Anki store your files on a local hard disk, as network filesystems can lead to database corruption. If a network filesystem is your only option, regular use of Tools>Check Database to detect corruption is recommended.

Running from a Flash Drive

On Windows, Anki can be installed on a USB / flash drive and run as a portable application. The following example assumes your USB drive is drive G.

  • Copy the \Program Files\Anki folder to the flash drive, so you have a folder like G:\Anki.

  • Create a text file called G:\anki.bat with the following text:

    g:\anki\anki.exe -b g:\ankidata

If you would like to prevent the black command prompt window from remaining open, you can instead use:

start /b g:\anki\anki.exe -b g:\ankidata
  • Double-clicking on anki.bat should start Anki with the user data stored in G:\ankidata.

The full path including drive letter is required - if you try using \anki\anki.exe instead you will find syncing stops working.

Media syncing with AnkiWeb may not work if your flash drive is formatted as FAT32. Please format the drive as NTFS to ensure media syncs correctly.


Please see this section.

Inaccessible Harddisk

If Anki can't write to files in the Anki folder, a message will be displayed on startup saying that Anki can't write to the harddisk, and Anki will close. If you're unsure how to fix the permissions, please contact someone near you who is knowledgeable about computers and can help you out.

Permissions of Temp Folder

Anki uses the system's temporary folder to store temporary data. If the permissions of this folder have been changed from the default settings by a rogue app or buggy antivirus app, Anki will not function properly.

If you're on a Windows 7 machine, the general steps to fix the problem are listed below. As this is somewhat complicated, please ask someone knowledgeable about Windows if you are not sure.

  1. Click on the start bar, and type in %temp% (including the percents), then hit Enter.

  2. Go up one folder, and locate the temp folder. Right click on it, and choose Properties.

  3. In the security tab, click on Advanced.

  4. Click on the Owner tab. If you're not listed as the owner, click the button to take ownership.

  5. On the permissions tab, ensure that you have full control. On a default W7 install the control will actually be inherited from c:\users\your-username.

Corrupt Collections

Anki uses a file format that is robust against program and computer crashes, but it's still possible for your collection to become corrupt if the files are modified while Anki is open, stored on a network drive, or corrupted by a bug.

When you run Tools>Check Database, you will receive a message if Anki detects the file has been corrupted. The best way to recover from this is to restore from the most recent automatic backup, but if your backup is too old, then you can attempt to repair the corruption instead.

On Linux, make sure sqlite3 is installed. On a Mac, it should be installed already. On Windows, download

Next, create a backup of your collection.anki2 file, in case something goes wrong with the steps below.


Open a terminal, change to the folder your collection is located in, and type:

sqlite3 collection.anki2 .dump > dump.txt

Open the resulting dump.txt file in a text editor, and look at the final line. If it reads "rollback;", change it to "commit;"

Then run the following in a terminal:

cat dump.txt | sqlite3 temp.file

Make sure you use temp.file - do not put collection.anki2 on the right, or you will blank out the file. When you're done, proceed to the final step.


Copy the sqlite3.exe program and your deck to your desktop. Then go to Start>Run and type in cmd.exe.

If you're on a recent Windows, the command prompt may not start on your desktop. If you don't see desktop displayed in the command prompt, type something like the following, replacing 'administrator' with your login name.

cd C:\Users\Administrator\Desktop

Then type:

sqlite3 collection.anki2 .dump > dump.txt

Open the resulting dump.txt file in a text editor, and look at the final line. If it reads "rollback;", change it to "commit;"

Then run the following in a terminal:

type dump.txt | sqlite3 temp.file

Make sure you use temp.file - do not put collection.anki2 on the right, or you will blank out the file. When you're done, proceed to the final step.

Final Step

Check that you didn't get an error message, and that temp.file is not empty. The procedure optimizes the collection in the process, so it's normal for the new file to be somewhat smaller than the old one.

When you've confirmed the file is not empty:

  • rename the original collection.anki2 file to something else

  • rename temp.file to collection.anki2

  • move collection.anki2 back into your collection folder, overwriting the old version

  • start Anki and go to Tools>Check Database to make sure the collection has been successfully restored.