Mailspring stores a cache of your mailboxes and your preferences in standard locations on your computer. Before deleting anything by hand, try the built-in options:

• Preferences > Accounts > Rebuild Cache... re-downloads a single account from the server.
• Preferences > General > Reset Cache deletes the local mail database for every account and rebuilds it. Your accounts, settings, and signatures are kept.
• Preferences > General > Reset Accounts and Settings removes everything and starts Mailspring fresh, as if newly installed.

Reset Cache leaves cached attachments in the files folder; delete that folder yourself if you also want to reclaim that space.

Deleting the data folder manually

To reset Mailspring completely, quit the app (including the tray icon), delete this folder, and re-launch it. You’ll be prompted to sign in to your Mailspring ID and connect your accounts again.

Here’s where to find the folder. Note that on some systems, this folder may be hidden from you by default. You may need to type in the path to the folder to find it, or remove the folder using the Terminal or Command Prompt.

Mac

~/Library/Application Support/Mailspring

Windows

C:\Users\<Your User>\AppData\Roaming\Mailspring

Linux

$XDG_CONFIG_HOME/Mailspring or ~/.config/Mailspring. If you installed the snap, the folder is ~/snap/mailspring/common.