If you have problems downloading from YouTube after updating to 8.77.3.1 choose one of these 3 solutions:
1) configure everything as explained in this guide VIDEO - DOWNLOAD OR TRANSMIT VIDEO FROM X - FACEBOOK - INSTAGRAM AND MANY OTHER SITES
or
2) install FIREFOX https://www.mozilla.org/it/firefox/new/
or
3) delete the MBStudio\yt-dlp.conf file