Bizarre M1 iMac keyboard/trackpad input issue
December 28, 2021 8:16 PM   Subscribe

A few times a month, unpredictably, my M1 iMac will suddenly just completely stop accepting (most) inputs from the keyboard and trackpad, and this will go on until I restart the computer. The "most" part is where it gets particularly weird — more details inside.

When this problem occurs, the mouse cursor still moves around, but I cannot click on things (and moving the cursor to the edge of the screen won't show the dock).

Likewise, the keyboard mostly doesn't work, but the function key row still does (volume controls, Siri, lock/Touch ID button, etc.), so my current go-to "solution" is to tell Siri to turn on voice control, and use that to do a soft restart rather than holding the power button to do a forced restart.

Even weirder, the regular keys do actually still work specifically for typing in my password at the wake screen, but stop working after that. The one exception is that if I turn off the keyboard and turn it on while mashing a key, I can usually get it to accept one keypress before the system stops acknowledging it again.

Anyone have any ideas at all what might conceivably be causing this? Third-party system extensions not playing nice with ARM are a very real possibility, especially given my use of Migration Assistant for setup, but I have no idea what. Also, notably, this happens regardless of whether the peripherals are connected via Bluetooth or USB. I'd love to not have to do a full system wipe and manual restore from backup, but I'm starting to worry that I'm going to be spending a day of my winter break doing that just to rule out the possibility…
posted by DoctorFedora to Computers & Internet (10 answers total) 1 user marked this as a favorite
 
Does the iMac only have 8 gigs of RAM? My M1 MacBook pro with 8GB does something similar if have too many safari tabs open and I max out the memory; but I never have the issue with my M1 Mac Mini that has 16 gb.
posted by jonathanhughes at 8:34 PM on December 28, 2021


Response by poster: 16 GB of RAM on here. For a while I had issues running out of system memory due to Rosetta bugs or something (switching to ARM builds of everything possible fixed this), but I think this is probably unrelated.
posted by DoctorFedora at 8:38 PM on December 28, 2021 [1 favorite]


Unfortunately I can't say specifically why this is happening, although memory pressure feels contributory when much the same occurs with my (much older) MacBook Air. The phenomenon is enough of a thing that there are a number of (temporary) fixit threads over the years and OSes with various theories but one recurring "solution" that boils down to: kill the Dock.

All this does - assuming it works for your problem like it does for mine and others' - is save you the full reboot. The Dock will restart itself in a moment and everything should work just fine again for a good long while.

Of course, issuing the kill command is difficult with most ways of inputting being compromised. When clicks and other keys aren't working, I can sometimes get it done by pulling up the Force Quit menu (Option Command Esc). If you can do voice commands, perhaps you can try setting up a kill Dock shortcut to see if this 'workaround' is of any use to you.

Nowadays I save aggravation by killing the dock via Activity Monitor at first sign of clicks or window movement becoming laggy/buggy.

PS. Just did a quick search for M1 kill dock and found a recent Reddit thread confirming (in the comments) the problem persists into M1 + latest OS, w no definitive cause https://old.reddit.com/r/MacOS/comments/ohlml8/dock_keeps_freezing_happened_multiple_times_now/
posted by to wound the autumnal city at 12:09 AM on December 29, 2021


Response by poster: Hmm, would the dock issue cause all mouse clicks and keyboard inputs to not work? Although deleting the dock plist seems safe enough as a tentative thing
posted by DoctorFedora at 12:21 AM on December 29, 2021


I’m curious if it is a Bluetooth issue… I’d try toggling it on and off, or plugging the keyboard in via USB (I’ve used my Apple wireless keyboard that way and it worked with Bluetooth off) and try a wired mouse if there is one easily available and turning it fully off.
posted by rambling wanderlust at 4:51 AM on December 29, 2021


Response by poster: As noted in the question, it happens both over Bluetooth and when connected via USB. It always happens simultaneously with both devices, even when one of them is plugged in to charge or whatever. It’s very weird!

(In my case I’m on the keyboard and trackpad that came with the computer, so either one can be used while plugged in to charge)
posted by DoctorFedora at 5:24 AM on December 29, 2021


I encounter a similar issue on my M1 MacBook Air. I'd say it happens at least once daily. I've been able to work around it by using an external mouse that has a USB radio receiver to put the Mac to sleep and then wake it.
posted by Transmissions From Vrillon at 8:23 AM on December 29, 2021


Probably not relevant, but I once had an issue w/ my keyboard acting wonky and it turned out the bit of software running the keyboard was corrupted. Was able to replace just that bit, didn't need to redo the whole system. Was many moons ago (~8 years?), but an iMac for sure.
posted by Bron at 8:55 AM on December 29, 2021


Response by poster: Hmm, if I knew which part of the system it is that handles keyboard and mouse (trackpad) inputs that could be replaced, that might be worth a shot. Do you happen to recall any more specifics?
posted by DoctorFedora at 2:22 PM on December 29, 2021


Response by poster: Hmm, come to think of it, modern versions of the operating system kind of partition off the OS itself into a section of the storage that isn’t really manipulable (and I’ve already done an OS reinstall that didn’t fix the problem)
posted by DoctorFedora at 4:40 PM on December 29, 2021


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