Uninstall Boostnote

There's no uninstaller, so you have to remove them by hand.

macOS

The application itself is located in /Applications/Boostnote.app, and the other data is located in ~/Library/Application\ Support/Boostnote/. You should remove them by following commands on your terminal.

$ sudo rm -rf /Applications/Boostnote.app
$ rm -rf ~/Library/Application\ Support/Boostnote

Even if you removed Boostnote, your data is still alive (remove it if you want).