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.
If you are seeing this, it is likely because your database size is too large or your cryptography settings are too high to be used in the Auto Fill context. The exact limit will vary depending on what device you are using also.
If you are using Argon2, it is likely caused by your Memory setting being too high. You could try to reduce this and see if that helps. You can do this using KeePass on Windows or KeePassXC on various platforms:
Using KeePassXC on Mac or Windows
- Unlock your Database
- Click on the Database menu item in the top left hand corner
- Click Database Settings
- Make sure 'Advanced Settings' checkbox is ticked in the bottom left corner.
- Click on Security
- Click on Encryption Settings
- Change the Argon2 Memory Usage. Set to about 16MB or so.
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.