User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:70.0) Gecko/20100101 Firefox/70.0

Steps to reproduce:

I open firefox and go on to youtube

Actual results:

thumbnails for the videos will not show up they are blank.

Expected results:

I should see thumbnails for the videos. But they will not show. I checked to see if it was a Youtube thing but when I tested on chrome they showed

having same experience for past week. video thumbnails don't load either in user channels, playlists, or the preview/up next pane on the right when a video is loaded.
issue was present in v69 so updated to v70.0 and still present. cleared entire cache & history, restarted, still present. all blockers disabled, still present. BUT this is only happening on my mac (high sierra OS); firefox on my pc is unaffected and functioning normally both v69 and v70.

forgot to add: safari on same mac also unaffected and youtube is functioning normally.

Hi,

Do you perhaps happen to have the Kapersky antivirus? Because if so, this is a duplicate of this bug: 1591374. On my end, I've tried reproducing this bug on FF 70 on MacOS Catalina (10.15) but don't get the error.

Regards, Flor.

I'm investigating the issue and I'll send more information soon. https://firefox-storage-test.glitch.me reports "Investigating... If this doesn't go away, things are unexpectedly broken." because even LocalStorage database for that site seems to be corrupted and script.js doesn't handle that currently.
For now, you can can fallback to the old LocalStorage implementation by changing "dom.storage.next_gen" preference to "false".

i do not have kaspersky... nor have i ever.

This is most likely due to image.webp.enabled being disabled in about:config.

(In reply to Kestrel from comment #6)

This is most likely due to image.webp.enabled being disabled in about:config.

tried it - it was set to false so i changed it to true - fixed! thank you :)

I have it fixed now it was the webp thing thank you for help