Please check the Dell Support forum, message http://en.community.dell.com/support-forums/software-os/f/4997/p/19643586/20794706 All details are in it. Basically the Dell shipped Windows install (W8.1) was cloned over to an SSD using the Migrate SSD 4.0 version. It worked like a charm. Never had a problem. Original hard drive was not re-formatted and one could boot to either drive and have it work. DISK MANAGER view is on the Dell site. Disk 1 is the SSD (on SATA III port 3). On Page 4 of the above link PLEASE read these messages: Posted by dilligas66 on Mon, Aug 3 2015 7:31 PM Posted by dilligas66 on Mon, Aug 3 2015 8:07 PM Posted by drjamison on Mon, Aug 3 2015 8:10 PM That is THREE of us, all used Migrate SSD 4.0 and we all CAN NOT install Win10 to that SSD. The first reference above even used the program to move from the SSD to the hard drive and could no longer install W10 to the hard drive when he could before: Contents of the message in the first reference above: ------------------ I used Paragon to migrate as well. That sounds fishy... I also used Paragon to migrate everything back to the platter, so the machine would be configured like it was when I received it. W10 install showed same error. 8.1 recovery disk to reinstall shows same error as well. Something has definitely happened, but I can't get my finger on it. ---------------- Can you tell us what might be going on?