Unlock Maps in Basecamp

I have just installed Basecamp on my new laptop and down loaded the latest Europe map to my Nuvi and my PC. It is OK on the Nuvi but it will not unlock on the PC.

I have been able to unlock, so it can be used on the PC, on my previous computer but I can not remember if there was anything special to do.

I have been through the unlock on-line process and it confirms that the map has been unlocked but the Basecamp software still says it is locked.

I have a Nuvi 2595, with unlimited map updates, and the latest map works fine on this device. I can even use this latest map direct from my device in Basecamp but this is a bit slow.

Can anybody help with this?