Something strange happened to my (powerful) MacMini. Since four days it is almost impossible to work with it. It has the newest Tahoe version installed. When waking up the screen after the night I got a message like “no more system memory available”. I force quit all applications and made a restart, still no remedy. Activity viewer shows “corespotlightd” process constantly using the Cpu at 200 or more %.
I disabled Siri in System Settings.
In Dorico I have to sometimes wait for
thirty seconds to input the next syllable of Lyrics. Selecting a note sometimes does not work, because some other action has not been
concluded. Spinning beachball almost constantly.
I can’t work like this. There is still around two thirds of unused hard-disk space.
It feels, if someone else is using my computer heavily in the background and I can only proceed, when “they” have a rest..
You know the guidance… Post your diagnostics so the team can take a look.
What do you also see - in terms of processes - in Activity Monitor, running which will (of course) also slow things down a little?
Run Mac diagnostics. From Google:
“To run memory diagnostics on your Mac, you can use Apple Diagnostics by shutting down your Mac, then turning it on while holding the D key until the diagnostics screen appears. This will help identify any issues with your RAM and other hardware components.”
Sounds to me like you have faulty RAM. That can happen.
Or its a job for the Genius Bar (do they still have that?).
Do you really have the latest Tahoe, that is 26.6, installed?
Please look into this path: ~/Library/Metadata/CoreSpotlight then press Cmd-I and report back with the size of that folder.
Launch Activity Monitor, switch to the CPU tab and report on usage from `corespotlightd`, or just type ‘spotlight’ in the top-right.
I’ve recently gone through this. If you have my same symptoms, I will share the solution (confirmed by other users on the Apple Discussions forum).
The percentage figure is per core, so on a Mac Mini with 10 cores, 200% leaves you with 800% to play with. So have a look at the total CPU usage numbers at the bottom of the window.
However, clearly, this is a system-wide problem, not a Dorico problem. Some system processes can sometimes go ‘crazy’, using large amounts of CPU, and it can be difficult to fix. If another restart won’t do it, then I would resort to killing the runaway process.
It’s worth mentioning that sometimes things like Spotlight do need to do some work, so it might be worth letting it run – but if it’s been going on for four days, then that suggests otherwise.
As that didn’t fix it, it’s probably best to enable it again.
I am posting my Dorico diagnostics here, although I guess the problem might lie outside the application.
The file is 6 MB, so I’ll post this link:
Thank you Michele,
I am running Tahoe 26.5.2
The size of that CoreSpotlight folder is 411.94 GB
I guess, that’s quite substantial…
My System HD (SDD) has the size of 2 TB - with 1.36 TB unused space.
The MacMini is equipped with 36 GB RAM.
Apple M4 chip.
Ah, to be exact, I disabled „Apple Intelligence“ and not Siri. Because I suspected it to use a big chunk of my computers calculation power. I have put it back on.
Hopefully that intelligence can help me solve the problem (-;
Great! We have the same problem, and let me guess, you also use Pages 
.
I have 2 TB SSD, with about your same unused space (lol) and also 36 GB memory. Only difference is the M3 Max SoC.
Now, please make a full Time Machine backup, then, copy that CoreSpotlight folder to an external drive. Next, move the CoreSpotlight folder to the Trash (with or without emptying it, it makes no difference), and restart your Mac. Log in and leave it ~10 mins to think about its life! After that, check the size of the CoreSpotlight folder and keep it under the radar for a few days to see how it goes (it should stay more than quiet).
This is what fixed the issue for me, and I did this when the CoreSpotlight folder was at 160 GB, so your current experience must be truly terrifying!
You may want to attempt something different before, though: try to just update macOS to 26.6 and see if it does its magic. I would personally still delete it anyway, since it is all cached material which will get rebuilt.
Let me know if this helps.
Thanks, @k_b; at first glance - and it’d be interesting to see whether it always likes like this - it seems as though Spotlight is taking an inordinate amount of CPU use. What happens if you disable Spotlight?
I have now updated to 26.6 and there seems to be some improvement; the snappiness is gone though. I will observe this for a few days, and probably at some point delete that folder. It shows “only” 300 GB now.
Indeed, give it a few days and, perhaps, leave your Mac running and not sleeping overnight so that macOS may perform its housekeeping.
I still believe you should run RAM tests. But when I suggest this, nobody ever does. Memory can develop faults.
RAM can get dementia and AI can hallucinate! 
Seriously, it wouldn’t hurt to check.
Also, Tahoe had some “fixes” to Spotlight in version 26.6 (26.6.1 is available). There are also links to methods on how to rebuild the Spotlight cache in Apple Support.
— Jim
I’m not convinced that a hardmware fault in RAM would cause this sort of error. The software is functioning “well” – it’s just doing something undesirable.
Memory faults would cause processes to crash or fail, because they can’t access locations, or getting wrong values.
I am abroad at the moment, but the last thing I noticed were some log entries with “filevault” in them… I checked and it seemed FileVault had been activated on my computer. I am sure I never did this myself (because I am not overprotective when it comes to computers). Anyway, I deactivated it, but that did not seem to make a big difference. I still have the mouse pointer/cursor stuck for 30 seconds or longer until I can proceed with absolutely normal tasks. So I left my computer running while being abroad 
at the moment. Once I am back, I will check my computer system again. And if it is still in that state, I will delete/destroy that Spotlight folder…
The process called kernel_task is not a real process at all. It’s the OS’s way of throttling the processor to avoid overheating, by blocking some of its capacity. Is your machine getting enough fresh air in all the heatwaves?