I'm having an issue with a version 10 back-up (several actually) when restored to Version 11. I've done this twice before on almost identical machines (Intel Atom Motherboard, 2Gb ram, Win XP Pro), they run fine. System has been running version 10 with no issues. Did two 3CX Back-ups, just to be on the safe side. UnInstalled version 10, re-booted, installed recent download of version 11, no issues. Applied most recent 3CX back-up, then applied Demo licence. Now everything seems fine...VoIP providers are up and registered, Firewall check passes, no error messages, but, no ATA' s or the gateway will register. There is no sign in the logs of incoming registration attempts, However I do see that the STUN server shows a failure (3 attempts). Wireshark run on the 3CX server sees the registration attempts coming from the ATA's, but no response from 3CX. Installation was attempted twice, no luck. Took the machine home and installed Ver 11 a third time, this time applying a backup from my own system (most ATA's, and the network /IP's set-up are identical), everything works just fine, which eliminates a hardware issue with the PC. So, I applied an older backup from the original location, same result, VoIP is fine, but no registration of any LAN devices. I've gone over all Network settings in 3CX, it all appears to be "normal" I can access the 3CX config page from another computer, and access from a browser to the net is fine. It's as if 3CX isn't monitoring port 5060, as the logs don't show any activity. I even changed the port number, saved it then changed it back...no dice. There is no difference, still doesn't work, even before the application of the Demo key. It is obviously something to do with the back-up that i am applying, but I'll be damned if I can pinpoint what it is. I ran out of time today, but i was going to attempt to apply even older Version 10 back-up. I really don't want to have to manually configure the whole thing over again. Any one else seen this sort of thing crop up before, any other suggestions?