com.apple.quicklook.ThumbnailsAgent CPU CPU Usage

Yes, this is an absolute shame that this is persistent since months and has not been addressed by Apple yet.

Please write here after wiping whether it works or not. If yes, then I will follow the same route.

It looks like this did it - https://developer.apple.com/forums/thread/79354

I just went to Settings --> Apple ID - and unchecked iCloud Drive - waited for that to process - then rechecked. Took 4 hours to download my 40+GB of iCloud data but after several restarts and using my MacBook like normal - no thumbnails agent. Also I'm noticing a vast improvement in OS speed having done this... I remember my Activity Monitor always being in the 20-40% after upgrading to Big Sur.

I'll report back if I see ThumbnailsAgent again but so far so good.

And it's back. Came back several hours ago and has been chugging away ever since. Guess I will be reinstalling Mac OS from the grounds up.

Thank you for writing. This is frustrating, spending hours and still getting the same problem. I have reported this to Apple support also that this problem is being faced by many users, but whether they are reporting it to the engineers is questionable.

Catalina 10.15.5, Just close Finder window, and the issue is been solved

I think this is related to indexing for Finder app. When your resources are idle it automatically indexes all the files in your Mac. It happened twice to my MacBook Pro(15" 2018) when I upgraded to Big Sur and two months after that. But Apple engineers will know better than me(the details)

Update:
After closing recents window it stopped consuming so much power. I guess I was wrong.

Its still persisting in Big Sur 11.3. CPU usage 150%.

Still the same under BigSur 11.4. After closing the Finder window it disappears

The thumbnail.agent is an app that (I think) goes into a file, reads it, and displays its content in thumbnail form.

It runs within Finder, obviously.

This happened to me because I had a huge pdf on my finder, which thumbnail.agent continuously looked into and updates (quick fix would probably be if Apple devs made it run every 10secs not continuously), a more decent fix would be to generate a less accurate thumbnail so it uses less resources.

User Solution: The moment you switch to another window in Finder where there are no big files you’ll be fine.

I host my big pdfs online now and open them in my browser to prevent this from happening. If you had to have them saved locally you could save them zipped or something.

Hope this helps!

I tried wiping everything and started from scratch. Huge hours put in... same issue. 70-80% CPU and max fan caused by com.apple.quicklook.ThumbnailsAgent (4988). It can be killed but starts right back up. I'd kill every thumbnail on my Mac if it would stop this.

Its been more than a year since this bug is persisting. Is there anyone testing Monterey? I hope its not there in Monterey!

I closed the opened Finder windows. The CPU automatically slowed down and the fans went quiet.

2018 Macbook Pro running Monterey 12.1 it's Thumbnailextension_macOS now but can confirm it's still an issue. I have to force quit it about once a day or it kills 99%+ of CPU. I can always tell when it's going because my fans spin up for no apparent reason.

This Error persist on osx 12.6 "Monterey"

How to reproduce this error:

press "Space" for preview on large 3D file, "STL, OBJ" point cloud. In 5 mins you can say good bye to your CPU and Memory because it's consumpt to 90%.