ProtonMail Bridge is an open-source application that allows you to fully integrate your ProtonMail account with any program that supports IMAP and SMTP. This includes Microsoft Outlook, Mozilla Thunderbird, and Apple Mail.
It runs in the background on your computer and seamlessly encrypts and decrypts your mail as it enters and leaves your computer.
Once you’ve installed and added your account(s) to ProtonMail Bridge, you will need to configure your email client. ProtonMail Bridge works with most email clients and applications that support IMAP / SMTP connections. In this guide, we provide step-by-step instructions for configuring Outlook 2016 for use with ProtonMail Bridge on your Mac.
How to set up Outlook 2016 for macOS for use with ProtonMail Bridge
1. Open Outlook and go to the Tools tab → Accounts.
2. Click the + icon in the bottom left corner → New Account….
3. Enter your email address and click Continue.
4. Choose IMAP/POP.
5. Enter the account details given in the ProtonMail Bridge app, then click Add Account.
Note: Do not use your regular ProtonMail account details. You must use the account details provided in ProtonMail Bridge under Mailbox details.
6. Go to the Tools tab → Accounts (see step 1) → Advanced → More Options…. and set Authentication as Use Incoming Server Info from the dropdown menu. Click OK.
7. Click Advanced and go to the Folders tab. Set Sent to Don’t store a copy of sent messages. ProtonMail Bridge will copy items into your Sent folder automatically when successfully sent.
Set Drafts to Drafts (On My Computer) to store drafts locally. Junk and Trash should use Outlook’s default settings (shown below).
8. Outlook will now fetch your emails, which can take up to five minutes. You can send emails immediately.
Note that when you create a draft in Outlook, it will only be saved and be accessible on the device that Outlook is installed on. You can now use Outlook 2016 with ProtonMail Bridge.
1. In split addresses mode every IMAP account that you set up with ProtonMail Bridge is address-specific, and will only be able to send and receive emails from the address it is set up with.
You can add any number of addresses to Outlook, but wait for one address to download before adding another.
2. In combined address mode, Outlook has no way to add more than one address to send with.
3. Keeping Outlook’s built-in spam filters enabled in addition to using ProtonMail’s spam filters provides additional spam filtering that uses the body of your messages to help detect spam. Any spam senders detected in this way will be added to your ProtonMail blacklist.
However, if you wish to disable Outlook’s spam filters and rely solely on ProtonMail’s spam filters, ensure that the Safe Senders and Blocked Senders lists are empty.