Big Sur lag when typing

Greetings Sergei_Usatov,

Thanks for reaching out. We understand that you've encountered a keyboard lag since upgrading to macOS Big Sur on your MacBook Pro. Thanks for sharing the steps you've tried thus far, including reinstalling macOS, and setting up the Mac as a new device. We'll be glad to share some steps to help us isolate the issue, and find the solution together.

• First, unplug any peripheral devices, speakers, external drives, USB hubs, and non-essential items from the Mac.
• Check to make sure all apps and the macOS software have been updated to the latest versions.
• Then open this link to learn How to use safe mode on your Mac. If the issue is resolved after booting into safe mode, then continue with the additional steps in the link. If it is not resolved in safe mode, then proceed below.
• Follow this link to the Activity Monitor User Guide and check for other anomalies such as a runaway process which may be affecting performance.

Keep us posted on what you learn. Thanks for your patience during this busy and exciting time.

Warmest regards!

Yesterday it got so bad that I started to turn off all Bluetooth devices (keyboard, mouse etc.) and only turn on one after the other after working for a while. It turned out that since I turned off the Magic Mouse the problem disappeared. Now I have the Magic Keyboard and Magic Trackpad (both newest generations) running and the typing lag disappeared. At least for now.

I have exactly the same problem(apart of the fact iMac starting up is like i go make my coffee, bake cookies and still the desktop icons isn't there) And that on an iMac (Retina 4K, 21.5-inch, 2017) purchased in March 2018 with 3.6 GHz Quad-Core Intel Core i7, 32 GB 2400 MHz DDR4, and Radeon Pro 560 4 GB( Fusion Drive 1TB) And as a technology avid guy i did all the resets, work around, clean up, testing, Disk Tool etc it simply doesn't solve the problem and my goal isn't to make a clean installation(not just yet) I find it ridiculous for a 2 year old machine( i used to say that for a PC...)

I got a hint from a fellow troubleshooter, his advice to fix the problem is by resetting the bluetooth module(no matter if you are using an external mouse/keyboard or not). Click on the bluetooth icon in the menu bar while holding down SHIFT OPTION. In case ShiftOption didn't work try the Factory reset all connected Apple devices (that did the trick for me on my iMac Retina 4K, 21.5-inch, 2017)

Hello Sergei_Usatov,

Thanks for sharing the additional steps you've completed, and the details about what you're continuing to experience. We recommend the following If your Mac runs slowly. If you continue to experience this lag, please Contact Apple Support directly for further assistance.

All the best!

Unfortunately, I am here to report that neither of the following suggested steps have resolved the keyboard/typing lag for me in Big Sur:

• Resetting the Bluetooth Module (despite using the built-in keyboard and bluetooth being off)
• SMC Reset (both T2 methods - power button technique and finger press twister (ctrl+opt+rshift+power))

The keyboard lag occurs in every app as well as in "safe boot" (which has additional performance issues of its own that concern me)

Same problem on my 2019 16" with Big Sur 11.0.1. Keyboard lag via the built-in keyboard in all modes (normal, safe mode, single user mode). No peripherals connected. Clean install. There was a comment elsewhere safe mode being nearly usable that I can also attest to. I wish I had known about these issues before I upgraded.

I have the same issue since I upgraded to Big Sur with MacBook Pro 13" 2018. Sometimes I cannot even type an email.

I use only Apple hardware incl. keyboard etc. I checked all the steps provided by Jeff but nothing helps. The MacBook Pro has a new battery and was freshly installed just weeks ago.

But it is not only the typing, also opening a new Tab in Safari is painfully slow even when there are no other apps running.

Activity Monitor doesn't show unusual processes, however I hear the fans very loud even with a CPU load < 10%.

Didn't have these issues with Catalina.

I have a new M1 Mac Mini (on Big Sur 11.1) and I was also experiencing HUGE lags while typing in any application, even when total (user+system) CPU usage displayed in Activity Monitor was less than 10%. Christos-Holland's suggestion of resetting the bluetooth module fixed it for me, at least for the moment.

I have the same problem - built-in keyboard lag seems to be ever so slight and constant now throughout my system, regardless of user, safe mode, or application. I've had some lag when typing this too. I did the "Reset Bluetooth Module" trick and it completely fixed the issue... but only once. I've tried all the Bluetooth reset tricks and they do not work anymore. I've had this since I upgraded to Big Sur, never happened in Catalina. I have a 5-month old 16-inch MacBook Pro, baseline with 16 GB of RAM, 512 SSD, 6-Core i7, and AMD Radeon Pro 5300m. This isn't something I would expect from a fairly new, $2,200 machine. I wish there was a solution.

Same problem on the newest fully specced out version of the 27" iMac running BigSur. I highly doubt the bluetooth module is the root cause. I keep bluetooth turned off, have a wired keyboard, and a USB mouse. The lag is the worst on iMessage, but occurs in other programs as well. I usually have to shut everything down and reboot to make it go away, but in a couple of days, it starts to come back and gets progressively worse, to the point where I can type a full sentence before any characters show up. Never had this problem with Catalina. It's but one of the issues with Big Sur, but definitely so far the most annoying.

I'm on 11.2.1 now and this problem persists. I've done a fresh install, smc resets, bluetooth module resets, prayers, etc. I've also noticed that my mouse cursor occasionally lags. I did go back to Catalina and these problems don't exist.

Ok, I suffer from the same issue. Not always only sometimes with my iMac Pro. And today I found a fix for me and reported it to Apple. I use the Mac with the Magic Mouse 2, Magic Keyboard 2 and the old Magic Trackpad 1. I had also some trouble with the trackpad, not working and losing connection. But rarely. Never thought about. Was typing today a big peace and I had the lag all the time. Driving me nuts. But for some reason I thought to shut down the Magic Trackpad. And it was gone. Keyboard worked from that moment perfectly while causes issues for hours before. Hope this helps.

That seems to have fixed my problem, thank you!