iCloud Photos sync paused because Mac needs to cool down - possible solution

I have also had problems with my Mac mini (2018) on Sequoia where iCloud Photos refuses to sync, saying “iCloud Photos sync paused because Mac needs to cool down”.

Tried the usual (clean dust, fan apps, etc). All temps looked normal, but the smoking gun was CPU throttling: pmset -g thermlog showed CPU_Speed_Limit around 60–70 (so the OS was actively limiting CPU even though the case felt cool).

What worked for me:

1. Reset the SMC. Shut down, unplug the power lead. Apple says ~15 seconds is enough; I left it unplugged longer and also held the power button for ~10 seconds while unplugged to discharge.
2. Run Apple Diagnostics (hold D at boot) to check sensors / rule out hardware faults.
3. Boot normally and leave the Mac idle for 10–15 minutes so Photos/iCloud can settle and resume its background work.

After that, iCloud Photos started syncing normally and the “needs to cool down” pause stopped occurring. I suspect the SMC reset plus giving the system time to stabilise on startup fixed it on my machine.