WebThumbnailExtension Web Content High CPU/Memory Usage

I've been running into this issue. Initially, I thought it was because my MBP M3 Max was connected to the Microsoft Redmond domain and that Intune MDM policies were buggy. I'm not sure QuickLook is the culprit (rather, I'm looking at you Excel and PowerPoint, or Teams 😏). Anyway, for awhile, whenever my CPU starts hitting 100% and computer starts becoming sluggish, I was using Activity Monitor to force quit all those pesky WebThumbnailExtension Web Content instances.

You can also use Automator to make an "app" that will programmatically kill those instances on demand. Here's the Run Shell Script I use:

#!/bin/bash

# Search for the processes and extract their PIDs
PIDS=$(ps -axo pid,command | grep -i "System/Library/Frameworks/WebKit.framework/Versions/A/XPCServices/com.apple.WebKit.WebContent.xpc/Contents/MacOS/com.apple.WebKit.WebContent" | grep -v grep | awk '{print $1}')

# Check if any PIDs were found
if [ -n "$PIDS" ]; then
    echo "Killing the following processes:"
    echo "$PIDS"
    echo "$PIDS" | xargs kill -9
    echo "Processes terminated."
else
    echo "No matching processes found."
fi

Hope this helps!

Just wanted to post that the solution here worked for me -

Looks like Quick Look is the culprit, and I never use it, so this was a pretty painless bandaid until they patch it.

Open System Preferences > Trackpad > Point & Click, and uncheck "Look up & data detectors."

[Edited by Moderator]

I have a new MacBook Pro M4 and have the same problem with the Web Thumbnail Extension taking nearly 100% CPU. I use Firefox, which triggers the issue, but it also happens with Safari. Opening MS Excel seems to exacerbate the problem.

Please, Apple, research and find this issue.

Thanks! That was really helpful.

I've also found another approach that can eliminate them even more efficiently!

TARGET_PROCESS="/System/Library/ExtensionKit/Extensions/WebThumbnailExtension.appex/Contents/MacOS/WebThumbnailExtension"

This is a Spotlight issue and a dreadful bug given that it makes Macs that cost several thousand dollars unusable. Sort it out Apple!

At the moment, the only solution I found is to close Safari, "Force Quit" every instances of "WebThumbnailExtension Web Content" in Activity Monitor, then use other browsers (e.g. Chrome, Firefox, etc.).

Has anyone tried doing a wipe and fresh install of the OS? I'm thinking of giving it a crack this weekend, but don't want to go through the hassle if someone has already tried and it didn't work. Otherwise, I'll report back.

Finally, I was able to solve the issue! You may kill running process, but this not solve the cause. Only allows you work for a few more minutes. It was frustratring.

I tried reinstalling/repair OS and did not helped either.

I got all cores under fire by opening Finder or using spotlights randomly. 100% utilization was caused by broken index and spotlight tried to index folder with large files, xml (and AI models in my case)

Only I had to do, was adding the folder to blacklist - prevent indexing.

Sequoia (15.3.1): System Settings -> Spotlight -> Search Privacy (at the bottom).

Add folder you want to exclude and wait for a while.

I started with home folder and gradually was able to isolate one project, that caused the issue. The rest of home folder has been reindexed and spotlight is working as has never before.

Just checking in to say that the clean MacOS install did not solve the problem.

I don't have any large xml files, so that's not it for me. I do have a large OneDrive folder with over a decade of documents. I keep it local on the mac. Spotlight seems to have indexed it just fine, but I'm wondering if that has something to do with it. I feel like MS/Apple are just never going to do anything about this, not sure what else to do since I'm locked to MS for work.

Same issue. Please help.

I came here to add that, while this has solved the problem for me about 80% of the time, it's still happening sometimes, and I don't know why. I think it might be tied to MS Office, but I have no idea how to confirm that, because it happens at random times.

Interesting. I escalated the issue to Apple Support and eventually spoke with a senior Apple tech who advised that the issue likely to be a bug when upgrading from OSX 14 to OSX 15. They suggested I do a completely clean reinstall which they are yet to guide me through. I am sceptical though, given the extensive comments posted here from people who already done this :-)

I also notice that the memory pressure issues seem to relate to use of Preview and Office when concurrently running. FWIW I did provide a link to this discussion group to the Apple tech, and suggested they look imto this in more detail.

the same issume，please help us

I have tried this method and disabled Look up & data detectors, but when I updated macOs Sequoia 15.2 the problem reappeared.Very disappointing experience, it's been 4 months now.

Double post, can't delete.