I have been getting an issue with the re-activation of license after upgrade to Windows 8.1
I have been in touch with the support @ unity but till this day no proper answer. Each time they ask either for serial number or computer name, which has been submitted multiple time.
I eventually un-installed and re-installed Unity 4.3 and still have the same issue. Anyone else have similar issue?
This is causing a lot of headache for me, as I am unable to view any of the work done by the team.
Vk
I can see from the support history and the Unity license database that currently your serial number is not activated on any machine. So, from the Unity point of view, you have a license that can be installed and activated on any two machines. The start of the support thread from Nov 18th has a screen shot showing an error message from Unity. Can you let me know what happens, step by step, when you press “Re-activate” from that window. If you get the chance, it’s worth trying to do a manual activation, using the instructions here:
(I can’t tell from the support thread whether you have tried this, or, if you even have the option of doing this.)
It’s always worth returning an activation before upgrading your OS.
Hope this will help you get back up and running on your Win8.1 machine.
I too am having license problems after updating to 8.1. When starting Unity3D i am meet with a window explaining that my OS seem to have changed and gives me the option to deactivate and reactivate the license. However when I press the reactivate button the window writes ‘Returning current license…’ but nothing further happens. The program does not freeze, but there is no progression.
I also tried reinstalling Unity, but it left me with the same message. I have contacted Unity support but have had no answer yet. I am kind of in a hurry to get this working as I am not able to do any work.
Graham Dunnett, I cannot get access to the manage license window to manually activate Unity as the program won’t move past the reactivation. How should I proceed?
How did you solve this noorcon?
Hello,
I’ve installed Unity3d version 4.3.1.
And, I can’t use the application, it says:
Then, I clicked Re-activate button.
I got this window, and it freezes:
Note: I’ve upgraded the Windows version from 8 to 8.1.
Before this upgrade Unity3d Version 4.2 were installed.
I have a non-pro version license.
I couldn’t use the instructions that Mr. Dunnett has given.
Best Regards
If you’ve updated to a new OS without first returning the activation, then please contact the support team and ask for assistance. Let them know the serial number and the machine that you have upgraded. (This is all documented, of course.)
Hi, I run into this problem after updating to Windows 8.1, then updating to Unity-4.3.3. I only use the free version too.
What i did to get this working was go to C:\ProgramData\Unity\ then make a copy of the ‘Unity_v4.x.ulf’ file just incase i needed it, then deleted it, Then i ran Unity again and it asked me for my email and password and all is working fine now.
Hope this helps. 
As Graham said… contact support.
Unity Support
Nuking the license file did it for me too - thanks @Slingshot.
I don’t have that file on my PC.
Deleting “C:\ProgramData\Unity\Unity_v4.x.ulf” worked for me.
Deleting Unity_v4.x.ulf works