I ran the previous version on Yosemite with no problems at all. After installing to 10.10.1, everything is insanely sluggish. I have another friend whom I have tried to fix similar issues on similar hardware, but found no solutions, now I am experiencing the same on my Mac mini mid 2010. Apps are taking looong time to launch. When they finally start, they are very slow to response. I can write a full sentence before even a single word appears on the screen. Anyone else experiencing similar problems? Any suggestions to sort this problem?