I've been successfully running macOS guests for many years with Parallels but I've run into a serious problem running Safari on Monterey guests on a Monterey host. The host is a MM2018 with 64GB of RAM running 12.3.1 and the guest is running the same macOS release. The problem is that Safari launches and is responsive until I actually try to browse a page. At that point, the page content freezes as does the scroll bar. Eventually, the screen will update and the scroll bar will resume. The length of the freeze seems to depend on the specifics of the content but is always 5+ seconds. Safari works fine on a Mojave guest running on the same host. As I recall, Safari ran poorly on Big Sur guest/Monterey host but I wasn't using it much and then made the mistake (in hindsight) of upgrading that guest to Monterey. To verify the problem, I created a new Monterey guest from the recovery partition on the host (Parallels said it was creating the machine using an Internet download). It went mostly OK although it froze on the final reboot into the new guest requiring a "reset" to get going and did the same after installing Parallels Tools. It also locks up the host for 5-10 seconds when booting (a problem noted by others that I've had mixed success with avoiding using "prlctl set <machine name> --video-adapter-type parallels" to change the video driver). Anyway, after the machine is created, I let Spotlight finish doing it's thing and I launch Safari first time. All the menu controls and the scrollbar work. I enter speedtest.xfinity.com into the address bar. The page appears as expected but the scroll bar is frozen while the Safari menu controls are fine. I click on the Test Speed button and nothing happens for about 30 seconds when the screen updates with an "in-progess" number and then 90 seconds later with the final result is shown (download speed is 200Mpbs). When I do the same test in Safari on the host, as soon as I press "Test Speed", the screen immediately changes, shows a test animation (which never shows on the guest) and updates a digital speedometer regularly until the test completes in about 25 seconds (download speed is 600Mbps). I tried Facebook.com and cnn.com and got similarly terrible results with the screen updating fitfully and the scroll bar not working. It tried google.com and when I typed something into the search box, none of the characters appeared for about 20 seconds. I've run Activity Monitor while repeating the tests and nothing interesting shows I've tried switching the hypervisor between Apple and Parallels, I've tried both the Apple and Parallels video drivers, I've tried an alternate guest network card, and both bridge/shared networks. I've run Activity Monitor while doing the tests and the CPU does briefly spike to 200% between "Safari Networking" and "kernel_task", it's only for a couple of seconds in the middle of the screen freeze. The scroll bar remains semi-frozen at the end of the test. Before I start the process of creating a ticket, I thought I'd see if anybody else is seeing the problem or has seen it and found a resolution.