30-09-2026 10:33 AM
01-10-2026 01:21 AM
Seeing a number of reports about this on Reddit, and here are the things people here can try:
1. Turn off the Ghostery extension for YouTube
It seems to be one of the main things people confirm caused them the issue
2. Clear the cache for YouTube
Click the shield (🛡) icon on the left of the web-address bar when you're on YouTube , then click "Clear cookies and site data" then Clear Data
3. Turn-off any custom filters if you use uBlock Origin
Click the uBO shield, then the cogs to go into the settings. On the "Filter Lists" screen, make sure you're only using the default filters, not things like "uBlock filters - Experimental". If you've subscribed to any of your own blocking-lists, try unchecking them also. Some people have said this has worked for them, but overwhelmingly Ghostery is more the issue.
Please check those things and see if YouTube is still an issue after.
30-09-2026 11:18 AM
@whiskey1337 : Not having any issues here: are you seeing this on all sites, or just some?
Have you tried going to Menu > Extensions and Themes > click the cog (⚙) > Check for Updates
Also try Menu > More Tools > Task Manager and click on the CPU column to sort highest-first.
Is any particular site causing high-usage at times you find it slow?
30-09-2026 11:54 AM
youtube mostly
01-10-2026 12:06 AM
Try going to Menu > Extensions and Themes > click the ⚙ icon > Check for Updates
It's likely to be an extension causing it
Extensions do not usually run in a "Private" window too
Try closing all YouTube tabs currently open
Then in the Firefox menu, click "New Private Window"
Try some YouTube videos in there
If they work correctly, then in non-private mode it'll be an extension causing it
30-09-2026 08:53 PM
The new update is extremely slow, YouTube is basically unusable. The CPU usage is moving between 100% - 49%. This update Suck. Please figure out what's happening and fix it. This is so bad I'm surprised this thing got released. hope this issu gets higher priority and get solved quickly.
01-10-2026 12:09 AM
Given YouTube is such a major site, I'm sure during testing this would have been noticed if it was a Firefox issue causing it
It's most-likely an extension
First go to Menu > Extensions and Themes > click the ⚙ icon > Check for Updates
Fully close all Firefox windows after, then bring up a new one
See if that resolves it
If not, make sure you've no YouTube tabs open in any Firefox window
Then in the Firefox menu, choose "New Private Window"
By-default, extensions do not run in private windows, unless you chose to allow them to
Try YouTube in that private window
If it works fine, then it's definitely an extension causing your issue normally
01-10-2026 03:58 AM
Seems to be the "Ghostery extension". I de activated it and the CPU usage went down.
01-10-2026 01:21 AM
Seeing a number of reports about this on Reddit, and here are the things people here can try:
1. Turn off the Ghostery extension for YouTube
It seems to be one of the main things people confirm caused them the issue
2. Clear the cache for YouTube
Click the shield (🛡) icon on the left of the web-address bar when you're on YouTube , then click "Clear cookies and site data" then Clear Data
3. Turn-off any custom filters if you use uBlock Origin
Click the uBO shield, then the cogs to go into the settings. On the "Filter Lists" screen, make sure you're only using the default filters, not things like "uBlock filters - Experimental". If you've subscribed to any of your own blocking-lists, try unchecking them also. Some people have said this has worked for them, but overwhelmingly Ghostery is more the issue.
Please check those things and see if YouTube is still an issue after.