Windows on a Mac
For those looking to add windows on there Mac Parallels is undoubtedly the best application to use. There is another application called VMware Fusion which is just as capable but in my personal experience Parallels is still the best in my view.
A few things to have and do before you add Parrallels, and this is you should have a machine with least 32GB Ram. The processor i7/i5 and a fusion internal hard drive. Yes SSD awesomely fast but have found time limited, only 10 000 hours working time, there after they tend to fail.
Ram on the Windows side should be at least half of what your are running eg. 32GB on Machine Windows 16GB. As have mentioned before in other articles update system, Parallels and any other 3rd party applications you may be running.