Mailspring stores your Mailspring ID password and your email credentials in your computer's keyring -- a database that encrypts your passwords on disk using your system's login password. (On Mac OS X, this is known as a Keychain).
Why am I getting a Password Management Error?
If you are getting a Password Management Error, it's because something went wrong when we tried to access your computer's keyring. This could mean that you don't have a keyring installed on your computer, or you are using Mailspring from a user account that doesn't have permission to access the keyring. Make sure that you aren't on a "guest" user account or any user account without a password.
I'm not on a guest account, but I'm running on Linux
If you are getting this error on Linux, and aren't on a guest account, it's likely that you don't have the proper keyring installed. Install gnome-keyring and/or libsecret from your package manager and try running Mailspring again.
I'm on Windows and I have a LOT of accounts
Windows has severe restrictions on the amount of data we can securely store. Since we store secure data for each email account you have, we've found once you link more than a dozen or so email accounts, we can approach the limit of the Windows password manager.
Thanks, but I'm still getting the error
If you still need help, we recommend you email firstname.lastname@example.org with a detailed description of the issue you are experiencing.