Since I upgraded to Monterrey, my MBP "stutters," i.e. it occasionally hesitates before completing an action.

This includes scrolling and typing, and isn't confined to any particular app...most annoying.

Is anyone else experiencing this?

First thought, try something like OnyX to delete caches? Second thought is out, since you can't use DiskWarrior...

At least someone is still in troubleshooting mode. Thanks for the suggestion.

I decided it was finally time to buy TinkerTool system, but since I've got a new MBP since the last time I d/l'ed it I was able to get it in "Evaluation Mode."

Now, fingers crossed.

Tried starting up in Safe mode or otherwise running without your legion of third-party enhancements?

For lack of a better idea, get TinkerTool and go to its General tab. There is a Keyboard option there that might help.

Here's another idea:

I am using Big Sur but I assume that the Keyboard pref pane is the same as in Monterey. Go to System Preferences > Keyboard and play with the settings. Also, try the settings in Accessibility > Keyboard > Hardware.

Good thought, but no go. Thanks anyhow.

"Legion?"

What do you know that I don't?

At any rate, I tried a safe boot, and, quite bizarrely, the problem was exacerbated. Go figure!

Thanks, Jon, but no luck.

Paying closer attention, I don't think this is a macOS problem, because it's not consistent.

It happens, for instance, at MacUpdate, but not other sites I've tested.

And it happens in Excel, but not all cells. (It may be time to try Numbers again.)

Time to try a shutdown / restart and log into your admin "Test" account to see if the issue continues there.....

Duh! Thanks!

I booted into safe mode (in macOS 12.3) as a troubleshooting step and was amazed by what I encountered.

My MBP was practically unusable! It was glacially slow.

Apps took forever to open, e.g., a Text Edit doc opened to a large, pixilated image of its icon, which remained on my screen for at least 30 seconds (during which period my MBP was frozen) before the doc's contents appeared Trying to quit TE sometimes worked and sometimes logged me out of my account.

Trying to QuickLook a TE doc yielded similar results.

The down arrow worked on a Safari page, but each click of the arrow key resulted in two steps to get one result.

I reran the macOS 12.3 installer, but nothing changed.

Anybody else?

Which model MBP do you have? How much RAM? How filled is the hard drive?

2019 16" MBP/16 GB RAM/129 GB empty space, but why do you think any of that makes the least bit of difference?

If it were to affect a Safe Boot, it would certainly affect a normal boot.

Leave it to you to find wierd problems.

What were your results when you booted from a test account?
If you boot normally does the slowdown disappear?

This is a long-shot but have you run Etrecheck Pro to see if it finds any anomolies? (I know the Pro version is not free, but I find its diagnostics more thorough and the explanations more thorough.)

A normal boot functions as expected, except for the noted anomalies, my test user account functions as expected, except for the noted anomalies, and EtreCheckPro doesn't show anything out of the ordinary.

Safe mode is still non-functional.

Has anyone been curious enough to try their own safe boot?

Given I am running macOS 12.3 beta on an M1 Mac mini I don't know how much, if any, comparability exists between our systems, but I am currently booted into safe mode and encountering zero performance issues. Certainly not anything like you describe. FWIW I have encountered a very rare image flutter when entering text in Safari Technology Preview but it was too intermittent and infrequent to be reliably reproduced. As a result of that, and other HTML rendering oddities issues, I have reverted back to Safari 15.4. I don't have any Microsoft Office products on my system and have not seen any anomalies anywhere else.

I'm encountering the same "stuttering" I experience in Excel while typing FTM posts in Safari, but it's not readily reproducible.

At this point, my options are down to clean install & migration, and nuke & pave, so I think I'll call Apple and dump the problem in their laps.

This is actually a fascinating problem, because there's no way it should be happening. If anything, performance is supposed to improve in safe mode.

The Apple tech I spoke to was as mystified as I was by both the "stuttering" and the weird safe boot, but she couldn't find any references to either problem, nor could she suggest anything that I hadn't already tried.

Sooo, I decided to do an erase > clean install > migration (which dovetailed nicely with the 12.3.1 update which was released yesterday), and after all was said and done, the "stuttering" persists, but safe boots work as expected.

I guess I've got no option other than to live with the "stuttering." ¯\_(ツ)_/¯

The tests are not as 'in-depth" as they could be and the diagnostic codes, in a word, suck, but I wondered if in all your troubleshooting with Apple, Apple Diagnostics had been tried. If not, they might reveal a hardware issue that has been overlooked. (Like the "indian-fighter" old westerns, used to say when hostiles were around, "I have an itch there may be a GPU (Graphics Processing Unit) or graphics memory issue lurking in your system." (I HOPE my itch is completely off-base).

Thanks for the suggestion. I had forgotten all about Apple Hardware Test/Apple Diagnostics.

Diagnostics took about 45 seconds to give my MBP a clean bill of health.

(Your link is dead. This one works: https://support.apple.com/en-us/HT202731 Use Apple Diagnostics to test your Mac - Apple Support)

It was live when I posted

For anyone who wondered, a comparison of the two links:

joemikeb - https://support.apple.com/en-us/HT20273
artie505 -- https://support.apple.com/en-us/HT202731