Windows lose focus after Big Sur upgrade.

Yep, exactly the same for me; external keyboard and mouse in my case, loses focus constantly whether I'm actively using the mouse or keyboard or not. I've already lost focus twice typing this message out. Other reports are that 3rd party programs running on your mac are causing it, I have very little running and none of the apps mentioned so far but will try that. Definitely making the user experience impossible.

Bump, same here, this has been happening to me since upgrading to Big Sur a few months ago. Incredibly frustrating — I've been using Macs since 1994 and have never had an app repeatedly stop me from typing, much less just become "unfocused" even though it's still the foreground app. I keep looking at my App Tamer list hoping to spot a culprit, and I've tried quitting any and all apps that I can to fix it, none of them seems to be a magic bullet. The only thing that fixes it for me is a restart, and having to do that every morning is tiresome. :(

Guys, this is a valid conversation, but it is completely off-topic. I can assure you that security software is not the source of the Big Sur window focus problem because I don't use any of the apps you're discussing and I have to deal with the problem every day*. I don't personally want to unsubscribe from this thread for that reason, I'm still holding out hope that a solution is found or Apple fixes it. Sooo... maybe start a new thread about security software and invite the active participants to it? 😬

* I'm starting to wonder if it isn't caused by a number of background-intensive apps, but no single app has turned out to be the culprit.

Hey I have this issue, and i don't have Norton. Window looses focuse even if I don't touch my laptop at all.

I think I'm on 11.5.2 on the machine in question; will try upgrading (but suspect that, for me, it's an app issue not an OS issue, given that it doesn't happen when I'm in the admin account).

The only issue I have with lost focus, other than what I previously described, is that my Magic Mouse 2 randomly disconnects from my new M1 mini — and may/may not reconnect on its own, or by my repeatedly clicking on it. This is an evolving problem as the mouse worked properly for the first two weeks that the M1 mini has been operational. No change in router location, or any other wireless changes from when the mouse was working correctly.

I have the same issue since the upgrade to Big Sur.

I'm using a Late 2013 13" Macbook Pro.

It's making the Macbook unusable.

It even happens when I'm not even using the mouse or trackpad... The 11.1 update didn't solve the issue.

To add to your discovery: first, there is no reason to ever install or run any 3rd party "cleaning", "optimizing", "speed-up", anti-virus, VPN or security apps on your Mac.  This user tip describes what you need to know and do in order to protect your Mac: Effective defenses against malware and other threats - Apple Community.  

There are no known viruses, i.e. self propagating, for Macs.  There are, however, adware and malware which require the user to install although unwittingly most of the time thru sneaky links, etc.   

Anti Virus developers try to group all types as viruses into their ad campaigns of fear.  They do a poor job of the detecting and isolating the adware and malware.  Since there are no viruses these apps use up a lot of system resources searching for what is non-existent and adversely affect system and app performance.

There is one app, Malwarebytes, which was developed by a long time contributor to these forums and a highly respected member of the computer security community, that is desshoigned solely to seek out adware and known malware and remove it.  The free version is more than adequate for most users.  

Also, unless you're using a true VPN tunnel, such as between you and your employer's or bank's servers, they are useless from a privacy standpoint: Public VPN's are anything but private.  

Juar some food for thought.

Old Toad, can you please help me understand why I don't need security considering the following experience. I visited a website that I visit on a regular basis. One day I went there and BitDefender flagged the site as compromised. I then disabled BitDefender to test the Mac's effectiveness in catching the hacked site. It did NOT. I enabled BitDefender again and ran a full system scan to ensure no remnants of my experiment remained. The site was repaired shortly thereafter, but this experience seriously limits my confidence in the built in security infrastructure in MacOS.

One other point. In the article you linked to, the author says that all such products are scams. There certainly are scams out there, but do you agree with the author's statement that they are ALL scams? That would mean Norton Security and BitDefender are also scams. If you agree with that, I wouldn't have a lot of confidence in your advice either.

michaelfjacob wrote:

One other point. In the article you linked to, the author says that all such products are scams. There certainly are scams out there, but do you agree with the author's statement that they are ALL scams? That would mean Norton Security and BitDefender are also scams. If you agree with that, I wouldn't have a lot of confidence in your advice either.

As they relate to Macs they are. Those types of apps are just not needed for Macs. MalwareBytes is all one would need. I have it but don't run it as I've never had to.

Another security trick is to do any web surfing from a non-administrative user account.

I very much appreciate the quick reply, but your answer doesn't explain why BitDefender was able to detect the compromised web site and MacOS failed to do so. Without BitDefender, MacOS would have left me vulnerable to any malicious activity on the compromised site. How does that qualify as "not needed"? I think there is value is security software for the Mac based on this incident alone.

Sorry about that! It's just that I am also experiencing the Big Sur issue with my windows losing focus. In fact it just happened again while I was typing this message. Someone said they resolved the issue by uninstalling their security software and I wasn't comfortable with that suggestion without further clarity, but your point is well taken. Thanks for the feedback.

No worries. :) And if removing this or that app solves the issues for you, that's great! So far no such solution has crossed my path — I've selectively killed almost all running apps and still had the problem until giving up and restarting. So frustrating, and such a crazy-making symptom.

I appreciate the standardized troubleshooting steps, but they don't apply to this problem for at least two reasons:

1. Restarting always fixes the problem temporarily, at least for me. But it also invariably comes back.
2. The problem sometimes takes a long time (maybe hours, maybe days) to start occurring.

...so the "remove software, try again" procedure just isn't feasible, it might take weeks for you to get to the root of the problem. I'll add here that my suspicion is that it just isn't any one thing, especially because no one here has identified a single piece of software that all or even most of the victims are using. So far my best guess is that it's related to sheer processor load — the more things you have going on, the more likely it will slip into this "mode."

Misery loves company! This focus switching with Big Sur is maddening. What tool could be used to discover which app is the culprit? It's not clear how to find it using Activity Monitor...I removed all autostarts, but it still happens every 2 seconds...