Freeze when Caps Lock is pressed on MacOS


Whenever I’m composing an email and I try to type capital letters with the Caps Lock key activated, Mailspring becomes non-responsive for a bit (I would say at most 20 seconds). Sometimes I get the OS warning to close the app because it’s not responding, other times it unfreezes after a couple of seconds

Note that nothing happens when I first activate the Caps Lock key, it’s only when I try to type next. This issue happens both when I’m composing an email in a new window and in the reply area inside a thread.

I also checked that I don’t have any key shortcuts tied to the Caps Lock key.

This is of course a very small bug and easy to work around (e.g. using the Shift key for capital letters), but it’s getting annoying.

To Reproduce…

Steps to reproduce the behavior:

  1. Start composing an email (either new window or as a reply in the thread)
  2. Press Caps Lock key to activate capitals
  3. Start typing in capitals mode
  4. Mailspring freezes (typed text does not show up, spinning color mouse cursor)
  5. Mailspring unfreezes after a few seconds, previously typed text shows up

Expected Behavior

To type with the Caps Lock key activated without the app freezing.


Here’s a gif showing the behaviour:

Screen Recording 2024-02-02 at 13.14.30

Here’s the frozen app warning:

Screenshot 2024-02-02 at 12.57.15


  • OS and Version: macOS 14.3
    • Installation Method: installer
  • Mailspring Version: 1.13.3

Additional Context

I tested this just now on macOS Catalina (v10.15.7) but cannot reproduce the behavior. I’m using the same version of Mailspring. Perhaps this is happening on the newer versions of macOS? Also, are you using an Intel-based Mac or Apple Silicon (like M1/M2, etc.)?

This is an Intel-based Mac mini. In fact I just bought a new M2 Macbook (same OS version), and it seems like this doesn’t happen there…

Thanks for the reply. FYI I am testing with an Intel-based Mac mini (Late 2012) using macOS Catalina. I still can’t reproduce the issue. I suspect your issues are related to a third-party desktop/menubar plugin, third-party antivirus software, or a keystroke logger (hopefully not that one).

Glad you’re not seeing the issue on the new M2 Macbook :ok_hand:

1 Like

I am using mailspring Version 1.13.3 (1.13.3), on the device Macbook Air M1 2020 Mac OS 14.3.1 (23D60), and it happens everytime. its very annoying

have you found the solution? same bug here

Not really :confused: I just try to avoid using the Caps Lock key.

it is kinda weird that I have the same mac that my gf, and she have this bug, but not me

Me currently on sonoma 14.1 and she is whatever the last one is