iMac Late 2013 Processor: 2.9 GHz i5 Memory: 16 GB Graphics: NVIDIA GT 750M 1024 MB OS: OS X El Capitan 10.11 GM Guest OS: Windows 10 My upgraded Windows VM to Windows 10 became unusably slow - taking minutes just to boot up. Under Yosemite and Windows 8.1 it would take 15-20 seconds. I had a Windows 7 VM which still ran buttery smooth on El-Capitan so I decided to reinstall from a DVD Image Windows 10 Pro. I selected Other Windows. After the install I noticed Parallels Tools were unavailable - there is a setting under name where you select the OS to tune the VM to. Selecting Windows 8.1 resulted in the same slow as molasses experience but changing it to Windows 7 and everything ran great again. Installed Parallels Tools and it runs as fast as Windows 7 if not faster!
