very good addition. with him much more convenient.
can you add a feature, hide watched videos on the subscriptions page?

Hi dear Simon!
First, thank You for Your work.
And thank You for fixing minor bugs when displaying "watched" logo on playlist.
I have some comments for this extension. Recently (after the update of addon? or youtube?) watermark "watched" appeared in the upper left corner in full screen mode directly on playing video. I've seen this when watched playlist. Can You fix this, please?

Everything it does works very nicely. What it doesn't do is allow videos marked as watched to be unmarked.

Playlists have a minor decoration problem - watched videos on the playlist show a double layer of Watched.

Awesone, you open the video and automatically it is greyed out but it would be more awesome if we could manually mark the video as watched witout actually open the video.

Five stars for using screenshots of Kyde & Eric's channel. The add-on is good too. Wish it didn't mark livestreams as watched while they're still going, only once they are over and archived in their entirety.

Essential for youtube.
In rare cases marks not watched videos as watched.

Great AddOn but it stopped working today.
Here is what happened, maybe someone can help me: today I ran CCleaner and then no more videos were marked.
I tried to reinstall the Addon, I tried to reboot the PC but both didnt work. I then tried to use the History Synchronize button and it says "synchronizing with history" but the progress stays at 0 and the "close"button is greyed out and I cant click it. I am desperate and I dont know what to do anymore :/

edit: ty for the fast response. Problem is fixed!

Great and a"must have" addon for Youtube users.

Feature request:
Add a feature that it removes watched from the https://www.youtube.com/feed/subscriptions when the video is marked as a watched. Give users a options when it removes them (when the video is full watched, 50% watched and so on).

Simple and works like a charm.

Essential for anybody who is really into YouTube.

Not sure it works permanently. Old videos I've watched are not being marked.

I'm looking for an extension that permanently stores YouTube history, and this seems to be a decent but imperfect solution.

TOP!! Works fine!

Thank you for making this addon for firefox. its working so far, this is the firefox version that im using (57.0 - 64bit)

worked very well until i updated to ff 57. totally loved it when it worked.
since updating to 57 my history and database are empty. and sadly no more "watched" videos.
when click on "synchronize" in the history-options a unclickable message saying "synchronizing with history" appears but nothing else happens until i reload or close the tab.
the search wheel at the buttom right is constantly turning but not finding anything.
already tried reinstalling the addon, overinstalling the browser and restarting the mac (os 10.12.6). it's just not working anymore.
on my older mac with el capitan this great addon strangely still works under ff 57.
any ideas?