Hi, try setting the player to Cinema Mode.

Octanas said

As the tile says, after upgrading to version 57, YouTube player got smaller when seen at 100% zoom but, if the zoom is changed to 90% the player gets to the usual size. Is there any fix to this situation as I don't want to change the zoom level depending on the website I'm browsing?

Here are some picts showing the situation in hand in comparison to what I get with IExplorer (on the 3rd pict).

I have a similar problem, only I keep the page zoomed at 90% and it's gotten smaller. When I zoom to 100%, the video moves to the center of the screen, with all the text underneath it, instead of remaining in the left column with text on the right. Internet Explorer still has larger videos in the left column. I do NOT want to use cinema mode; I want the video in the left column. I'm not sure if this started with version 57 or version 58, but I suspect it is due to a recent upgrade. How can I the video back to the previous size?