Longtime Duplicati user. On a Windows 10 machine, 2.3.0.1_stable_2026-04-24 was running for months with no apparent issues. Then I noticed tray icon was missing. Tried restarting Duplicati ->didn’t work. Tried rebooting → didn’t work. Downloaded and installed latest 2.3.0.4, thinking it might have fixed something. But it still wouldn’t start. Digging deeper now, looked at crash log and it starts with this:
Duplicati.Library.Interface.UserInformationException: Server crashed on startup
—> System.Exception: A serious error occurred in Duplicati: Duplicati.Library.Interface.SettingsEncryptionKeyMismatchException: Encryption key used to encrypt target settings does not match current key.
Note that no configuration or anything was intentionally changed between everything working and it failing.
I never explicitly encrypted the database, but I see in the release notes that 2.3.0.0 adds a default secret provider, and sure enough, when I look in the Windows Credential Manager, there is an entry for duplicati-server-encryption-key.
So I tried launching Duplicati.GUI.TrayIcon.exe with the --disable-db-encryption, but it fails with the exact same output.
Other than doing a fresh install, I’m now at a loss as to what to do next to get it working again.
This message means that Duplicati found an encryption key, but it was not the right one.
Did you by any chance run a “cleaner” program?
I am aware that some cleaner programs have a setting for “remove intranet credentials” or similar wording, that will actually wipe the Windows Credential Manager for all credentials.
Duplicati prior to 2.3.0.4 had a logic bug where it would create a new key if it could not decrypt the database. While this did not break anything directly, it can be really confusing if the real key was wiped, as you would see a key, but it would not be the right one.
Yes, without the key, the database cannot be decrypted.
If you have the backup configurations exported, you can rename the Duplicati-server.sqlite file to get a clean slate.
I will try to add a wipe-encryption method that will purge the database of encrypted content so you could run that first, and then go and manually enter the things that were wiped (encryption passphrase, destination url, etc).
No, nothing was done on this machine that I might suspect would modify the Credential Manager.
Unfortunately, I didn’t export it first.
That would be fantastic. Alternatively, is it straightforward enough for me to use a sqilte DB editor to replace the “enc-v1” fields in there with their plaintext versions (unless the format has changed recently, I can look at one of the backup server DBs for examples), delete the key in WCM, and relaunch? (I do see a lot of encrypted fields in the Option table that I know nothing about and wouldn’t touch, though, e.g. jwt-config, pbkdf-config…)
Thanks for your help. (Honored to be receiving it from duplicati’s creator).
@kenkendk Update: Duplicati is working again for me after using your new wipe-encryption command (from 2.3.0.108_canary) and then resetting the passphrase and target URL. I still have no idea how there ever was an encryption key mismatch, but thank you so much for the convenient tool to fix it!!
Just as a data point I would like to say this occurred for me yesterday (2026-08-09) running 2.3.0.107-1 Canary build on CachyOS (Arch Linux) therefore this is not just a Windows issue. I rebooted my computer and duplicati went from running fine to showing a crash error (upon automatic startup of the Tray service at user login). Error message is the same:
`Duplicati.Library.Interface.UserInformationException: Server crashed on startup
—> System.Exception: A serious error occurred in Duplicati: Duplicati.Library.Interface.SettingsEncryptionKeyMissingException: Encryption key is missing`
I have the backup configuration saved so I will just attempt an erase and reinstall as a solution. But thought you would want to know in attempting to trace the cause.