The same here since the update to Parallels 14 and MacOS Sierra - iMac, MacOS Sierra, 3.1 GHz, 16 GB RAM, Fusion Drive. Windows 10 starts between 6 and 9 minutes. Windows user interface very very slow Hello ArtistW, this issue has already escalated to the Tier 2 team and our development team is still investigating this issue internally. That is now 6 months ago and until today no solution My only "bad" solution: I have now a Samsung SSD 500 GB increased, Windows.pvm copied to it and see there Windows starts in 22 sec and the entire Windows system environment runs so much better. But that can not be the solution and I want to control everything from the internal hard drive. But the error is definitely not on the installed Windows system.