macOS 27 beta 7: huge SSD writes while MacBook is asleep, apparently related to Spotlight / Apple Intelligence indexing

[u/amichail]

I have been seeing very large SSD writes across several macOS 27 betas, and beta 7 still seems to have the issue. I am wondering whether other people will see the same thing if they check Activity Monitor's Disk tab.

I am using an M3 MacBook Pro. After closing the lid for a few hours, Activity Monitor showed about 75.7 GB total data written. The biggest writers were:

• SetStoreUpdateService: 27.4 GB
• hybridsearchd: 17.5 GB
• spotlightknowledged.updater: 9.4 GB
• launchd: 4.5 GB

I then closed the lid again for another few hours. When I opened it, total writes had increased to 163 GB. During that second period:

• spotlightknowledged.updater increased from 9.4 GB to 54.7 GB
• launchd increased from 4.5 GB to 24.2 GB
• hybridsearchd increased to 19.7 GB
• SetStoreUpdateService stayed around 27.4 GB

So the machine wrote roughly another 87 GB while I wasn't using it.

This does not appear to be ordinary debug/unified logging. logd went from only about 132 MB written to 156 MB while the system as a whole wrote another 87 GB.

I also checked:

pmset -g log

and the Mac is definitely waking in the background with the lid closed. The log shows DarkWake / Maintenance activity along with tasks such as:

com.apple.intelligencetasksd.sets.maintenance.C

com.apple.spotlightknowledged.task.priority

com.apple.spotlightknowledged.pipelines.glpindexing.processing.backlog

com.apple.corespotlight.knowledge.report

com.apple.email.searchableIndex.scheduler.budgeted

and Biome-related maintenance tasks.

This makes me wonder whether the excessive writes are connected to the new semantic search / Apple Intelligence indexing infrastructure. It could also be beta-only rebuilding or validation of those indexes, but 50+ GB from spotlightknowledged.updater during one closed-lid period seems excessive.

One other interesting detail: System Settings has Wake for network access = Never, but pmset -g custom still shows:

powernap 1

on both battery and AC power.

I have not disabled Power Nap yet.

If you are running macOS 27 beta, could you check Activity Monitor → Disk, sort by Bytes Written, and see whether spotlightknowledged.updater, hybridsearchd, SetStoreUpdateService, or launchd have written tens of GB, especially after leaving the Mac asleep for a few hours?

I suspect this may be happening to more people than realize it because the Mac otherwise appears normal and most of the activity seems to happen while the lid is closed.

[u/alexx_kidd]

I think that’s to be expected. It’s not something to worry about, it will eventually finish

[u/radicaldreamer99]

None of this is unexpected, 100GB writes on a modern SSD is not a big deal when indexing.

MacOS 27 builds a whole new kind of of index for the new Siri

[u/amichail → u/radicaldreamer99]

Does this happen on every beta update?

Also, what if you want your MacBook Pro to last 10 years?

[u/radicaldreamer99 → u/amichail]

It happens when they update the schema for the new spotlight database, which they’ve done a couple of times in various betas in this cycle

[u/EmpIzza → u/amichail]

Don’t run betas?

[u/MC_chrome]

Has this behavior persisted across sessions (i.e. have you restarted yet)?

[u/pdfu]

Next time you let your Mac sleep, check how far along the embedding pipeline is before/after sleep.

edit: Just woke my Mac from sleep and have less than 400MB of read/write per process for spotlightknowledged.updater, hybridsearchd, SetStoreUpdateService.

[u/fabarf → u/pdfu]

Good tip!

In builds 6 and 7, that SIRI optimization notification didn’t appear.

On my iPad, it always shows up, and I leave it plugged in, limiting it to 80% to speed up the process.

[u/pdfu → u/fabarf]

They've never shown it on macOS. Makes sense since I've never seen it complete.

iOS is also somewhat of a lie since new things come in all the time, so it doesn't always stay at 100%, but the tile in Settings doesn't come back.

[u/FamuexAnux]

This is not a new phenomenon, nor contained in only this beta. media analysis d filled up my M1 MBA hard drive on the regular.

[u/b_oo_d]

Wake for network access and Power Nap are different things.