Thanks folks, will try Ken's suggestion and report back.

jamesg1213
I would like to know what's caused it. I'm guessing it may have something to do with a W10 update a week or so ago, but that's a stab in the dark.

 
Just to add: from what we've noticed, this happens across the board for users who upgrade to Windows 10. It seems to give your OS a new Computer ID, causing the one to be seen on your XLN Account as 'wrong.' As Ken said in the second post, removing your old OS's registration from your XLN account and then adding it again with the Win10 details will correct this.
 
Joe

Joe Connor [Cakewalk]

jamesg1213
I would like to know what's caused it. I'm guessing it may have something to do with a W10 update a week or so ago, but that's a stab in the dark.

 
Just to add: from what we've noticed, this happens across the board for users who upgrade to Windows 10. It seems to give your OS a new Computer ID, causing the one to be seen on your XLN Account as 'wrong.' As Ken said in the second post, removing your old OS's registration from your XLN account and then adding it again with the Win10 details will correct this.
 
Joe

Not quite in this case Joe, my machine is a new build with W10 installed, not an upgrade. I downloaded AD2 shortly after I installed Sonar on it, which would have been around November/December last year. HTH.

FWIW, after receiving my new Win10 PC around October of last year and installing AD2, a Win10 update (I believe it was a large update 1151? around the time frame you mention) caused AD2 to need its license refreshed. It only happened the one time but the fix (same as msg#2) was easy.

There has been a new build of Windows 10 released in the last month and if it gets installed as part of a normal update it will invalidate the xln activation I have had this happen on 2 of my PC's so far not sure what triggered the update on 1st PC 2nd PC was by Microsoft to cure another issue I had installing an Akai driver.
 

scook
FWIW, after receiving my new Win10 PC around October of last year and installing AD2, a Win10 update (I believe it was a large update 1151? around the time frame you mention) caused AD2 to need its license refreshed. It only happened the one time but the fix (same as msg#2) was easy.

Looks like that's the culprit Steve, thanks. Removed the PC from my XLN account and renamed it, then it asked me to update AD2. Fixed.

Glad you are up and running again
All the best.