Half the websites I try to visit using Firefox in Windows 10 are having the same issue, most of the site is blacked out. This is happening in both my work and home computer.
Hi @Brent_Motl, it seems to be an issue with Firefox, not Parallels Desktop. When Firefox displays an image file, such as 1-pixel GIF file (often used for tracking), it displays the image on a dark background. Does the URL you're visiting end with an image extension (or have an image extension followed by a question mark and then various parameters)? If not, a script on the site may be serving you an image instead of a web page for some reason. Some firewalls like Kaspersky can block content and send a 1x1 GIF image instead. You can try it for Kaspersky installed: Protection > Firewall > Filtration system: disable the "Banner Ad Blocker".