I have completed the licence arrangement, where I received my serial number for Photoshop CS6 Extended, which was a download ( the first time I have not had a physical version ). The product is installed, and running fine on my IMac Intel. However, I have always preferred to register Photoshop, as I have done since version 7, but when I attempt to do this, I recieve a message that my serial code is invalid ! I have double and triple checked this to be absolutely sure that the serial nuber is the one I received, and which is running Photoshop, but I just keep getting the same message - most frustrating !
I am not on a subscription, as I only use Photoshop in conjunction with a number of 3D software, but would prefer to have the product registered, but I seem to have hit a brick wall on this. Any suggestions please ? I am on some very tight deadlines, so don`t have much additional free time to spend trying to figure this out, but always ready to listen to good advise 
Many Thanks.