AutoFill Sometimes Crashes or Disappears on Me. Is My Argon2 Memory Is Too High?

If you are seeing these issues, it is likely because your database size is too large or your cryptography settings are too high to be used in the AutoFill mode (the exact limit will vary depending on what device you are using). We discuss both issues below with suggested fixes.

Argon2 Memory Usage
If you are using Argon2 or Argon2id as your Key Derivation Function (KDF) then your memory setting must be below 64MB to function in AutoFill mode. You can view and change these settings within Strongbox on iOS. To do so follow the instructions below or watch the video below:

  1. Unlock your Database
  2. Tap the 'Database Settings' icon (the icon with three sliders in the top left of the screen)
  3. Tap 'Encryption'

Here you can see various settings. If you have Argon2 enabled you will also see a Memory parameter. Please ensure that it is set to 64MB or less (we recommend 32MB just to allow some margin).

Database Size
If your database is quite large, it can also be a challenge to decrypt and encrypt it in AutoFill mode. One thing you can do it to make sure that your KeePass database is using the latest KDBX4 format. You can also check and set this format using the same instructions as above. However, instead of changing the Argon2 memory, instead make sure your Database Format is KDBX4. There will be a small orange warning indicator if you are not using the latest format. This format allows for far more efficient encryption/decryption, and Strongbox has been optimized for this format. This should help reduce the size of your database also.


This is related to Apple’s App Extension Resource Budget policies. Apple allows App Extensions (which is what the Strongbox AutoFill component is) only a very small portion of system resources, and terminates the process very quickly and without warning if it exceeds certain CPU/Memory usage limitations. Unfortunately part of what makes Strongbox the most secure password manager depends on using a lot of resources to protect your secrets. Ultimately and unfortunately, there isn’t much Strongbox can do about this. Apple’s limitations are somewhat arbitrary and not open to appeal. This is a difficult situation for a Password Manager to be in, because CPU/Memory is a large part of opening an encrypted database.

Jan 5, 2024