I installed my upgrade from MC14 to MC15 this morning and the registration process would not work. The correct MAC address was pre-inserted by the upgrade process in the non-editable field, byt the program claimed it could not find my sales order number in its database. I could see no way to provide that information since none of the fields screen could be edited.
I finally went to the licensing section of the PTC Support site, moved my license for MC15 from the correct MAC address to another MAC address on the same machine. I was then sent the two new license files by e-mail, and they worked.
But, I needed to move the license back to the original MAC address, since the MAC address I used to get past the non-working upgrade license process "disappears" when the computer is not connected to a hard wired Ethernet connection.
I went back on PTC Support and moved my license yet again from the substitute MAC address back to the original MAC address, which is a WiFI adapter.
I received my two new license files, but, the license wizard in MC would not run as long as it thought it had a valid license.
So, I disconnected the Ethernet cable, which made that adapter disappear, and enabled WiFi. When MC failed to find the licensed alternate MAC adapter it opened the license wizard and allowed me to install the new license tied to the WiFi card. This has the very same MAC address that was in the ID field during the upgrade, so it remains a mystery why I had to jump through so many hoops to get my upgrade licensed.