Using Claws Mail with Gmail

Gmail account setup

In your Gmail settings, turn on "Enable less secure app access". (Gmail's "enable less secure app access" is a euphemism for "apps that don't support OAUTH2", it does not mean programs such as Claws Mail, are less secure.)

You will also need to use an App Password to log in if using two factor authentication on your account.

Incremental drafts are not supported

Gmail does not support incremental saves to Drafts and will create one file per save.

You need to either go to '/Configuration/Preferences/Compose/Writing' and turn off 'Automatically save message to Drafts folder every [...] characters', or use a Drafts folder which is not on the Gmail IMAP server.

Claws Mail account setup

Open your account preferences, and make sure these options are set:

on 'Basic' page

server for receiving: imap.gmail.com

SMTP server (send): smtp.gmail.com

User ID: [your complete gmail email address]

on 'Receive' page

Authentication method: Automatic

IMAP server directory: [leave empty]

on 'Send' page

[x] SMTP Authentication (SMTP AUTH)

Authentication method: Automatic

on 'TLS' page

IMAP: Use TLS

Send (SMTP): Use STARTTLS command to start encrypted session

on 'Advanced' page

SMTP port: 587

IMAP port: 993

Set the [Gmail]/Trash folder as Folder Type 'Trash' on the General page of the folder Properties, so that emptying Trash really deletes the messages it contains.

Additionally, as gmail cannot handle incremental saves to the Drafts folder, turn off 'Automatically save to Drafts folder every n characters' on the /Configuration/Preferences/Compose/Writing page.