Like many others, I cannot activate Parallels 10 on a replacement Mac. Old computer "died", and I migrated the data from the external backup of that computer to my new computer using Yosemite and Windows 10. Parallels is not installed on other computers. I've been using Parallels for years and have never had this issue. What is the workaround? There is no support phone number or email for tech support. I REALLY need access to my Parallels 10.