The new Proton Mail Bridge is a major improvement

Proton released an update for Proton Mail Bridge that promises major performance improvements over previous versions. It is also the first version that is optimized for Apple Silicon on macOS.
Proton Mail users who want to use the secure email service with traditional email programs, such as Apple Mail, Microsoft Outlook or Thunderbird, need to use a dedicated app, called Proton Mail Bridge, to do so.
Proton Mail Bridge, which we mentioned in 2017 for the first time here on this site, adds end-to-end encryption support for Proton Mail to desktop email clients. Proton Mail is one of the few email services that uses end-to-end encryption and zero-access encryption all the time. The company can't access emails of its customers. This encryption is automatic when Proton Mail users use the web-based version or the Proton Mail apps.
It is a problem if customers want to use other desktop programs, as these do not support the required functionality to decrypt the messages. That's were Proton Mail Bridge comes into the picture. It bridges the gap by introducing the missing support.
Note that Proton is working on a dedicated Proton Mail app for the desktop operating systems Windows, Mac and Linux.
The new Proton Mail Bridge
Proton engineers have developed an improved version of Proton Mail Bridge. It includes "major performance and stability improvements", according to the company's announcement on the official blog.
Proton Mail Bridge is available for Windows, macOS and Linux to all paying Proton Mail customers, but not to Proton Free users. Proton Free is an introductory plan that is free of charge, but limited in functionality and capabilities. It is limited, for example, to 1 free email address and 150 messages per day.
The first commercial plan, Proton Mail Plus, starts at €3.99 ($3.99 US) per month, with options to save up to 24% when subscribing for a two-year period.
Proton claims that the new Proton Mail Bridge application synchronizes inbox data up to 10 times faster when compared to the previous version of the application. Additionally, the sending of emails with large attachments is now up to three times faster than before. Another major benefit introduced by the update is that emails may now be composed and sent right away. Previously, the inbox needed to be synced first before that was possible.
Setting up Proton Mail Bridge on new devices or logging in after a time of absence should now be much faster, according to the announcement.
Behind the scene, Proton engineers developed a new IMAP library, which they called Gluon. This app uses a snapshot-like system, that assigns each email app its own snapshot of the email inbox. Bridge uses the information that is provided to handle all email activity more efficiently. Gluon is open source, and the code is available on GitHub.
Proton has started to roll out the Proton Bridge Update to customers on February 20, 2023. Customers who do not want to wait and new customers, may download the latest version of Proton Mail Bridge from the official website right away to update to it immediately.


You said that Outlook isn’t your main email client, so which is your main one?
I think its thunderbird
It is Mozilla Thunderbird.
Awesome! This actually solved my problem… what a stupid bug.
If this is the same bug that I’ve encountered, there may be another fix: (1) hover over open Outlook item in Taskbar, cursor up to hover over Outlook window item, and right-click; (2) this should give you Restore / Move / Size / Minimize / Maximize — choose Move or Size; (3) use your cursor keys, going arbitrarily N/S/E/W, to try to move or size the Outlook window back into view. Basically, the app behaves as though it were open in a 0x0 window, or at a location that’s offscreen, and this will frequently work to resize and/or move the window. Don’t forget to close while resized/moved, so that Outlook remembers the size/position for next time.
THANK YOU Claude!!! I could get the main window to launch but could not get any other message window to show on the desktop. You are my hero!!!!
Solved my issue! 6 years later and this is still problem…
Fantastic. Thank you. Size did the trick.
This solved my Outlook problem, too. Thank you. :)
Thank you so much, this started happening to me today and was causing big problems. You are a life saver, I hope I can help you in some way some day.
You are a god – thank you!
thanks a lot…. work like charm.. :-)
Yah…thanks Claude. I’ve been having the same problem and tried all the suggestions…your solution was the answer. It had resized itself to a 0/0 box. Cheers
Excellent post. This had me baffled even trying to accurately describe the problem. This fixed it for me.
Thank you
Thanks a lot for the article. Don’t know why it happenend, don’t know how it got fixed, but it was really annoying and now it works :-)
Thanks a lot. I was facing this issue from past 3 week. I tried everything but no resolution. The issue was happening intermittently and mainly when I was changing the display of screen ( as i use 2 monitors). The only option i had was to do system restore. But thanks to you.
I’ve been tried to sole this problem for 12hours. Your comment about changing the display of screen helped me a lot!! Thanks!!
Thank you…don’t know why this happened but your instructions helped me fix it. Running Windows 10 and office pro 2007
Great tip! Thanks!
Worked for me, too – thank you!!!
It’s Worked for me, too
thank you very much!
I had a similar issue with Outlook 2013 on Windows 10 and this helped me to fix it. Thank you very much!
Thank you so much. Solved!
Considering you published this in 2012, incredible not been debugged by Microsoft.
Thank you again. M
This problem was faced by only one user logging to TS 2008 r2 using outlook 2010.The issue was resolved.
Thanks.
Great tip. Thank you!!!! If it helps, I had to use the Control Key and the arrow keys at the same time to bring my window back into view. Worked like a charm.
Thank you, this worked !!!!
Man, you are a fucking god. Thanks a lot, what an annoying bug!!
Awesome, this post solved the issue. Many thanks!