This is a Nice n’ easy one.
If you’re getting this error it could be that you have just tried to install the WP-Mail-SMTP plugin for WordPress.
The reason you are getting this error is because you’ve probably had this plugin installed before and the directory structure still exists.
Plugin Install Failed.
*Destination folder already exists*
Delete it (and it’s remaining contents) and try again.
Thanks for your visit 🙂