I tried to update to Parallels 17 this weekend and it made quite a mess. I run a bunch of macOS VMs (Catalina and Big Sur 11.5.2) on a macOS host (Mac Pro 2019 running Big Sur 11.5.2). All ran perfectly under v16, but after updating to v17, the Big Sur VMs crash during startup, about halfway through the progress bar. The Catalina VMs can't handle much network traffic: when they are running apps that stress the network, they start dropping pings. The strange thing is that even after I reverted back to v16, the same stuff is happening. And it's happening even with restored VMs from before the v17 upgrade, ones that it never touched. So it seems like v17 did something to my host machine that destabilized it, especially with network connections. The "uninstall" for Parallels is just dragging the app to the trash, but I think there's something lingering somewhere from v17. My environment is pretty unique, so not sure if too many other people will see this, but wanted to put it out there in case others are thinking about updating: give it a few more versions until they discover and fix some of this weird stuff. I have a Support ticket in, but this is so weird that I don't have much confidence that they'll be able to offer much, unfortunately.