High Memory Usage by spotlightknowledged on New MacBook Air M4 After macOS Tahoe Update – Normal or Fix Needed?

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High Memory Usage by spotlightknowledged on New MacBook Air M4 After macOS Tahoe Update – Normal or Fix Needed?

Hi everyone,

I'm a new Mac user and just set up my brand-new MacBook Air M4 (with 16GB unified memory) a couple of weeks ago. Everything was running smoothly until I updated to macOS Tahoe 26.0.1 last night. Now, every time I wake the laptop from sleep or open it, the process spotlightknowledged spikes to an insane 40+ GB of memory usage in Activity Monitor (under the Memory tab). This causes noticeable lag, high fan noise, and even prevents normal shutdown sometimes—I have to force quit it or hard reboot.

From what I've read, this seems tied to Spotlight indexing, but on a fresh install like mine, I'm wondering:

Is this normal behavior right after a Tahoe update, especially on M4 hardware? (I've seen similar reports on Reddit about memory leaks in Tahoe, but mostly on older M1/M2 models.)
Or is it a bug/leak specific to the new OS version?
What should I do to stop this from happening repeatedly? I've tried force-quitting the process and rebuilding the Spotlight index via Terminal (sudo mdutil -i off / then on /), but it comes back after sleep. Should I wait for a patch, exclude certain folders, or something else? Any safe tweaks for a newbie without risking data?

Thanks in advance for any advice—excited about my first Mac, but this is a bit frustrating!

[Edited by Moderator]

MacBook Air 13″, macOS 26.0

Posted on Oct 18, 2025 12:57 AM

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Answer 1

TheLittles

Level 10

204,449 points

Oct 18, 2025 1:13 AM in response to bieeyx

bieeyx Said:

"Now, every time I wake the laptop from sleep or open it, the process spotlightknowledged spikes to an insane 40+ GB of memory usage in Activity Monitor (under the Memory tab). This causes noticeable lag, high fan noise, and even prevents normal shutdown sometimes—I have to force quit it or hard reboot.[...]"

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Thank you for the screenshot.

RAM Clog After an Update:

Try rebuilding the Spotlight Index. Go here: Rebuild the Spotlight Index on your Mac - Apple Support. Having performed an update, the Spotlight Index may be loading. So, once this is performed, leave it on for a few, without touching it, and see if it then works. Perform this in Safe Mode. While booted in Safe Mode, login items do not open at login, and certain items can be fixed. Go Here: Start Up your Mac in Safe Mode - Apple Support

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Answer 2

Owl-53

Level 10

104,593 points

Oct 18, 2025 1:54 AM in response to bieeyx

You have done what you can by rebuilding the Spotlight index

Some suggest, as this is the latest and greatest offering ( M4 MBA ) from Apple, for the moment

Just to turn Off the computer at days end.

My 15" M4 MBA also with 16 GB Unified RAM and 500 GB SSD drive can boot up from Off to On in a matter of about 2 - 4 seconds

The Tahoe 26.0.1 update seems to have been issued more so to fix this issue

https://www.macrumors.com/2025/09/29/apple-releases-macos-tahoe-26-0-1-with-m3-ultra-bug-fix/

Now that Apple has announced a M5 MacBook Pro that will be available October 22, just days from now

Also reading elsewhere, that these machines will require a Tahoe update out of the box

I could be reasonable to possible conclude the Beta Tahoe 26.1 may drop fairly soon there after

Wrap this all up - hold off doing a dramatic changes and digging deeper on this issue until the 26.1 is released

OP wrote " This causes noticeable lag, high fan noise, and even prevents normal shutdown sometimes—I have to force quit it or hard reboot."

This computer is a Fanless computer that is 100% reliant on the Outer Metal Case to dissipate the heat as will as proper ventilation underneath and around the external of the computer

Apple has given its MacBook Air 15 the lightning-fast M4 SoC, which is still cooled passively. It also features a new 12 MP webcam .

EDITED

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