Did you recently upgrade your operating system?
Do you have KMyMoney 5.0 or above?
Did you try to open your kmymoney sqlite database and your password will not work (and you have no recollection of changing it, but maybe you did?!??)
Good news, you're not crazy. You're in the open source wild west.
KMyMoney uses sqlcipher for its encrypted sqlite databases. At some point it upgraded from sqlcipher 3 to sqlcipher 4, and the new version cannot open the old databases! They don't even tell you this, and neither does KMyMoney.
Luckily the fix is not hard.
1) Install the sqlcipher tool on your computer (eg, sudo apt install sqlcipher)
2) Open your database: sqlcipher path/to/mydb.sqlite
3) Run these commands:
After that, you should get a single row containing '0', indicating success (another number indicates failure).
PRAGMA key = 'your_passphrase_here';
PRAGMA cipher_migrate;
you can .quit and uninstall sqlcipher if you choose.
Done. You should now be able to open your database with the latest KMyMoney. phew
Reference: It's all made very clear in the second paragraph of the subsection on "File (SQLite/SQLCipher only)" in chapter 22 of the online manual
