Hi Parallels, This appears to be an issue that has come up for a lot of parallels 12 users, but I have not found a resolve yet. I am about to fully re-build the VM, but was hoping for a last minute break-through. I'll keep it to the point, some of which is borrowed from another outdated forum here. Machine: Macbook Pro 15" Mid 2015 2.5GHz i7 16GB & AMD Radeon R9, OSX El Capitan 10.11.6, Parallels 12.2.1 (Among other versions through attempted fixes), Windows 10 Pro. This is a personal machine and the partition is a work partition, managed mostly by IT, with an Admin account then my work profile. Problems (somewhat chronologically, over less than two weeks): (This has all been very intermittent, everything has happened several times, and there's really no rhyme or reason, or consistency). Occasionally the network would disconnect. This was okay, I only needed to disable and re-enable the adapter in windows - quick fix. Then, when loading, the computer would tell me it couldn't load the start-menu and desktop, but if I restarted it ran just fine. Then, it got stuck at the welcome page, either indefinitely, until it told me "Invalid handle...", or until I gave up. I restarted enough times, then ran start-up repair, waited for 30 minutes while it seemed like it was updating, then it worked again. After a while, startup repair would't even work, then later on it did work. Everything just took forever to move from one step to another. Then (yesterday) I logged in and got "c:\WINDOWS\system32\config\systemprofile\Desktop is unavailable. .... etc" and the start-menu wouldn't work, profile files for office and AutCAD wouldn't load, certain product registrations weren't registered. For a while, it could log into windows through bootcamp alone, but the was finicky, even with the Admin profile. At one point, I got this blue screen that said something about a EUI or something. Basically a big NO. Things I've tried: Updating parallels and parallels tools. Creating an entirely new user profile. Startup Repair Talking to parallels live-chat and giving them remote access, to no avail. Deleting and reinstalling parallels, including installing Version 11, upgrading back to 12. Deleting and re-adding the virtual machine. Removing parallels tools manually, including from the (windows) registry, & reinstalling. Adjusting C: permissions of the user profile. Trying out VM Ware, stuck at welcome screen. C:\Windows\system32\ctfmon.exe A TON of resetting. Basically, shits gone down hill the more I get in to this. It appears that Parallels (no, not windows) has corrupted the user files that windows uses when it loads. I'm about to format the partition and start from scratch. This is all I've got left, and I've got no recourse for it not happening again. I'm thinking of going to VM Ware Fusion, or downgrading back to Parallels 11 after the installation. The parallels tech support has not been helpful and I'm pretty disappointed with this; parallels has been very good for a long time.