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Issue metadata

Status: Verified
Closed: Sep 2015
EstimatedDays: ----
NextAction: ----
OS: Linux , Windows , Chrome , Mac
Pri: 1
Type: Bug-Regression

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uBlock Functions Inconsistently on YouTube

Reported by, Aug 29 2015 Back to list

Issue description

UserAgent: Mozilla/5.0 (X11; CrOS x86_64 7405.0.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/47.0.2495.0 Safari/537.36
Platform: 7405.0.0 (Official Build) canary-channel auron_paine

Steps to reproduce the problem:
1. Watch some YouTubes videos for a while, make sure to   select different videos from different youtubers. 
2. Reload a video repeatedly, sometimes the blocker works and sometimes it doesn't.

What is the expected behavior?
Ads are always blocked.

What went wrong?
Ads load on videos and they don't have the skip button either. 

WebStore page:

Did this work before? N/A 

Chrome version: 47.0.2495.0  Channel: canary
OS Version: 7405.0.0
Flash Version: Shockwave Flash 19.0 r0

This behavior is really random and can be hard to reproduce.

The developer has an issue open, but can't reproduce:

Here's a couple of threads in Reddit of users complaining about the issue:
What kind of indication do you have to think that this is a Chrome problem, and not either: the extension itself, or google just trying to find workarounds?

I've been having similar problems, the first time I noticed it I purged all cache in the ublock extention and then redownloaded the rules.  It seems to stop the problem for a while, then it came back.  It comes and goes, strangely enough.

Comment 2 by, Aug 29 2015


A. Installed an old build of uBlock ( and it still malfunctions in 47.0.2495.0 and 46.0.2490.4
B. It works correctly with latest stable build of uBlock on 44.0.2403.156

Seems like an issue in Chrome and not a problem with uBlock, YouTube ad conspiracies or a 3rd party filters issue.
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By the look of the "Non-functional_uBlock.png" screenshot, this suggests network requests are not passed to uBlock's chrome.webRequest.onBeforeRequest() listener. The yellow lines are from uBlock's content script.

Comment 4 by, Sep 2 2015

This seems to affect all ad blockers in general. Adguard for example is ineffective on YouTube as well.
Another user of uBlock Origin reported an issue, and also in this case it is as if uBlock Origin's chrome.webRequest.onBeforeRequest handler is no longer being called at all: the extension's own logger is empty, and the count of network request blocked is zero -- despite the extension being otherwise up and running:

Looking at the changes to the chrome.webRequest code in the last month:

In particular, I see code to filter out chrome.webRequest listeners has been added:

Makes me wonder if there could be an unforeseen side effect which causes legitimate chrome.webRequest listeners from suddenly being filtered out.
Status: Assigned (was: NULL)
Confirmed that this happens with all adblockers, though I haven't tested with an older version of chrome. We'd need to do a bisect, I had originally assumed it was an issue with youtube changing something.

Rob, could this be your change? As a reviewer... well, it seemed ok to me at the time.

gundlach, CC'ing you in case you've been investigating this on your side, and suspect Chrome.
I think I've figured this out. It was a security fix tracked in  bug 510802  which we can't make public yet, but it has the details.

Comment 8 by, Sep 4 2015

Shuld I investigate this further, or do you want to take it from here?
I'll respond in other bug.

Comment 10 by, Sep 4 2015

Status: Started (was: NULL)
I'll take a look.

(This is the 2nd bug in a few days where we accidentally got a hosted app and treated it like a full extension. I wonder if we should type-safety-ify this and change the method to take a filter. Some other time perhaps.)
well, the workaround here would be simply removing YT app from chrome.

Comment 13 Deleted

Comment 14 by, Sep 6 2015

Labels: -Pri-2 -Type-Bug Pri-1 Type-Bug-Regression OS-Windows OS-Linux OS-Mac M-45
This bug affects everyone who has installed a hosted app and use some form of ad/request blocker. This may affect the UX of millions of users (since 45), so I'd like to merge the patch ( with 45 if possible.
The original bug and fix ( Issue 510802 ) is now public, so those following can see the history of this bug. 

Comment 16 by, Sep 8 2015

 Issue 527878  has been merged into this issue.

Comment 18 by, Sep 9 2015

Labels: Merge-Request-46 Merge-Request-45
Status: Fixed (was: NULL)
The fix is now live in Chrome Canary (47).

Requesting to merge 1db473b2e3b66646a7470e543540a44e854cd8f7 with M-46 and M-45. See #14 for impact.
Labels: -Merge-Request-45
Thanks Rob.

Let's merge to 46 first, let it bake for a bit, then merge to 45. There's no imminent release of 45, so there's no value in rushing to get this into a Stable patch.
Labels: -Merge-Request-46 Merge-Approved-46 Hotlist-Merge-Approved
Approved for M46 (branch: 2490)

Comment 21 by, Sep 9 2015

From a user perspective: we'd really like to see this bugfix in Stable asap. We're losing customers (& revenue) every day due to our extension (Mixmax) failing to load due to this bug. We don't have a workaround (due to other bug Please, please merge into stable!
Rob - please merge to M46.

#21 - Note that "merging to stable" is not the same as pushing a new stable release. Even if we merged to stable today, the fix won't be available until we push a new release. We also need to make sure that we get good test coverage in M46 before merging to M45.
Project Member

Comment 23 by, Sep 10 2015

Project Member

Comment 24 by, Sep 10 2015

The following revision refers to this bug:

commit 91802ce0e3305c4fa5f38416f19058b323386fc1
Author: Rob Wu <>
Date: Thu Sep 10 07:38:40 2015

Labels: Merge-Request-45

Comment 26 by, Sep 11 2015

Labels: -Merge-Request-45 Merge-Approved-45
Let's get this in M45 branch 2454 today if possible. Thanks!
Rob - whenever you're ready (and awake), please merge to branch 2454.
Project Member

Comment 28 by, Sep 11 2015

Comment 29 by Deleted ...@, Sep 11 2015

I don't understand one thing; if this fix is merged in 2454 are we going to get a new stable release with this fixed? And if so, when? 
Labels: Needs-Feedback
Tested the same on mac 10.10 chrome version 47.0.2495.0 with the below steps

1. Added the uBlock origin extension and navigated to youtube and played different videos
2. Observed that the ads are getting blocked as expected

Please find the screenshot

Could you plesae provide the clear TEST steps to verify the fix from test team end as we can not repro this on reported version with above steps.
Screen Shot 2015-09-14 at 3.40.20 PM.png
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#31 A which is a duplicate of this one has a nice small test case:

Comment 32 by, Sep 14 2015

To verify this bug, you also have to install the YouTube app:

When the bug was present, requests to were not visible to extensions such as uBlock origin.
With the bug being fixed, such requests do show up again.
Labels: TE-Verified-45.0.2454.93 TE-Verified-M45
Status: Verified (was: NULL)
Verified the fix with Chrome version 45.0.2454.93 on Windows(7/10), Mac and Linux(Ubuntu 14.04Lts) :

Steps followed :
1. Install and launch Chrome 45.0.2454.85
2. Install ublock extension from Chrome webstore :
3. Make sure to install youtube app :
4. To Make sure to check it's installed correctly open JS console and typr in "" which should return "true" 
5. Open app and play few videos in different tabs and make sure the videos have an ad's which play up front

Observed behavior :
-Ad's should be blocked and videos should start playing. 
-When the navigated to Chrome Incognito mode and played same videos ad's aren't getting blocked(As expected since the extension wasn't enabled in incognito mode).
-When the extension is enabled on incognito mode all the ad's were blocked.


Comment 34 by Deleted ...@, Sep 22 2015

Workaround / Solution:

1) Enter chrome://apps into your urlbar.
2) Rightclick on the Youtube Symbol
3.) Click "Remove from Chrome"

btw: which Chrome version has the natural fix?
Bild 2015-09-22 um 12.12.17.png
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Comment 36 Deleted

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