Active windows on my Mac Studio become inactive/lose focus

Does it occur while in Safe Mode?

Start up your Mac in safe mode - Apple Support

I’m having almost exactly the same issue on my 2019 MacBook Pro running MacOS 15.5. It does not happen when I boot in safe mode, but it resumed after I rebooted normally.

What’s different for me is that the first user that logs in after rebooting does NOT see this issue, but all other user accounts will have windows lose focus. Even after switching between accounts (both while still logged in and after logging out and back in), the first account will continue to run normally. Rebooting and selecting a different account to log in first will allow that user account to not lose the active window, but the other accounts (including the last one that was “first” before the reboot) will lose window focus every 1-5 seconds. 

It's been happening even with system windows, such as the "Are you sure you want to log out now" pop up. The length of time before the window is no longer active varies, so I might be able to get in a few letters before having to click back to the window, only for it to lose focus again within milliseconds, then lose it again after I get one character typed. Clicking so frequently often highlights the text I've already written and I end up typing over it and losing my progress. Poking around settings that require an admin password was a nightmare until I figured out the reboot trick.

It began happening sometime between June 23 and June 28, 2025.

KittyCornerCubby wrote:

I’m having almost exactly the same issue on my 2019 MacBook Pro running MacOS 15.5. It does not happen when I boot in safe mode, but it resumed after I rebooted normally.

What’s different for me is that the first user that logs in after rebooting does NOT see this issue, but all other user accounts will have windows lose focus. Even after switching between accounts (both while still logged in and after logging out and back in), the first account will continue to run normally. Rebooting and selecting a different account to log in first will allow that user account to not lose the active window, but the other accounts (including the last one that was “first” before the reboot) will lose window focus every 1-5 seconds. 

.....

It began happening sometime between June 23 and June 28, 2025.

If the problem does not exist in Safe Mode, then it usually means the problem is related to some third party software that is installed. If it only occurs with some user accounts, then it is more likely due to a Login Item that is common between those users.

This was happening for me. Following these safe mode instructions and removing logins items worked. Thank you!