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ProtonMail Bridge

Frequently Asked Questions

Commonly asked questions and answers can be found on this page.


The macOS and Windows versions of the Bridge are currently available for download for all paid users. The Linux version of the Bridge is scheduled for early 2018.

On macOS, we have tested the Bridge on Apple Mail, Thunderbird, and Outlook 2011/2016. On Windows, we have tested the Bridge on Thunderbird and Outlook 2010/2013/2016. Every client implements the IMAP standard slightly differently, so we cannot make any guarantees about how the Bridge will behave on clients other than the ones listed.

When settings up your email client (such as Thunderbird, Outlook, AppleMail), you must use your Bridge Password, not your normal ProtonMail account password.

After you add your account to the Bridge, you will be given a Bridge password. This is the password that you should use for setting up your account with your client.

Every client has a different way of handling Starred emails. On Apple Mail and Outlook, where stars are interpreted as flags, your Starred folder is called Flagged Mail. On Thunderbird, you can view all of the Starred emails in a mailbox by clicking the star at the top of the mailbox listing.

When you add an account to the Bridge it will initially be in combined addresses mode, in which emails from all addresses in the account will be received in the same mailboxes and by default sent with your primary address. If you would like to keep emails associated with each of your addresses separate, then you can switch to split addresses mode. In split addresses mode, you will need to add each of your addresses to your client separately, and emails will be segregated by address in different mailboxes. Unfortunately, if you are using Outlook, it is not possible to add additional sending addresses when in combined address mode, so split addresses mode is required if you would like to send from email addresses other than your primary email address.

Due to IMAP's incompatibility with draft updates, the drafts that you save on the Bridge will only be kept locally on your computer and not sent to ProtonMail's servers. Go to https://protonmail.com/bridge/clients to see how to set up your local drafts folder on each client.

Yes. The Linux release of the Bridge is scheduled for early 2018.

ProtonMail labels are represented as folders in your client. To create a new label, add a new folder under the Labels folder.

To label a message without removing it from its current location, copy the message into the relevant label folder. This works the same way as labeling on the web and mobile applications. To label a message and remove it from its current location, drag or move the message into that label folder.

The Bridge has not been designed to work on mobile platforms, although we may work on a solution for this in the future.

Yes, you can add multiple accounts to the main Bridge screen, and you will get a different Bridge password for each of them. You will have to add these accounts separately to your client of choice.

The Bridge uses ports 1143 and 1025 by default but sometimes one or both of these are already in use. You can change these in the Bridge by going to:
Help > Advanced settings > Change SMTP/IMAP Ports
You can increment the port numbers (i.e. 1144 for IMAP / 1026 for SMTP) until you have ones that are not occupied by another application.

Once you change the port make sure you also update the port settings in your email client.

You can configure this in your Bridge settings - it will be turned on by default. In some cases, you may see an error indicating that autostart is not possible due to your permissions settings.

To fix this on macOS, navigate to your LaunchAgents folder (/Users/<username>/Library/LaunchAgents) CTRL + click Get Info Sharing Permissions, and make sure that the user and administrator have both read and write permissions.

To fix this on Windows, navigate to your Startup folder right click Properties Security and make sure that the user has both read and write permissions.

Need help? Email Bridge Support