Difference between combined addresses mode and split addresses mode
Proton Mail offers the ability to have multiple email addresses within the same account.
If you have a Proton Free plan, you may have an email address like user@proton.me and a short domain address(new window), user@pm.me.
If you have a paid plan, you can create even more addresses(new window), including with custom domains(new window).
In the Proton Mail web and mobile apps, all of the emails you send and receive from all of your addresses appear in the same folders (e.g. Inbox, Sent, etc.) within your account. When using Proton Mail Bridge(new window), however, you have the ability to choose between combined addresses mode and split addresses mode.
In combined addresses mode, emails from all the addresses in your account will be sorted into the same mailbox folders in your email client. The default “From” address will be your primary address (though it is possible in Thunderbird and Apple Mail to add additional sending addresses). Combined addresses mode is the default setting when you add an account to Bridge.
In split addresses mode, emails associated with each of your addresses will be kept separate, and you will be able to toggle between “From” addresses in the Composer in all supported email clients(new window) by default.
If you are using Outlook, it is not possible to add additional sending addresses in combined addresses mode. You must switch to split addresses mode if you would like to send from email addresses other than your primary email address.
Switching to split addresses mode
If you have not yet configured your account in your email client:
1. Turn the Split addresses switch on.
2. Click Enable split mode in the confirmation box that appears.
If you have already configured your account in your email client:
1. You will need to remove the account in your email client by following the steps in the section below.
2. When you have finished removing the account, reset Proton Bridge. To do this, go to Settings (gear icon) →Reset Bridge (you will be asked to confirm your choice).

3. Sign back in to Proton Bridge and enable split addresses mode (as described above).
4. Re-configure your account in the email client by following the steps for your client(new window). Near the end of the setup process, you will be asked to add each email address separately.
Removing your account
Thunderbird for Windows
1. Click on Tools and select Account Settings.
2. In the left side of the window, select the address you wish to remove.
3. Click on the Account Actions menu bar and select Remove Account.
Outlook for Windows
1. Go to Account Settings.
2. Select the account you want to delete and click on “Remove”.
Apple Mail
1. Click on the Mail menu and select Preferences.
2. Click on Accounts, then highlight the account you want to delete.
3. Click on – (the minus sign).
4. When prompted, click Remove or OK, and then close the Mail preferences window.
5. Go to Settings →Profiles and remove “Old Profile”.
Thunderbird for Mac
1. Click on Tools and select Account Settings.
2. In the left side of the window, select the address you wish to remove.
3. Click on the Account Actions menu bar and select Remove Account.
Outlook for Mac
1. Click on Tools and select Accounts.

2. On the left side of the window, select the account you want to delete. Then click the “Delete” button.
3. Select Delete.