Add your serial number to the account if it is not already added.
Click Activations to the right of the serial number.
Click Disable all Activations.
Unfortunately you cannot return single activations, this only resets them.
If your machine is still accessible:
You are now able to manage your license from the editor. Below is a guide to how this system works and performs.
Click the Unity drop-down on your toolbar (Help on Windows OS).
Click the Manage License option. (This is the unified place within the Editor for all your licensing needs).
The License Management window will appear. You then have four options, explained below:
Check for updates
Cross-references the server, querying your Serial number for any changes that may have been made since you last activated. This is handy for updating your license to include new add-ons once purchased and added to your existing license via the Unity Store.
Activate New License:
Enables you to activate a new serial number on the machine you’re using.
Return License
Enables you to return the license on the machine in question, in return for a new activation that can be used on another machine. Once clicked, the Editor will close and you will be able to activate your serial number elsewhere. For more information on how many machines a single license enables use on, please see our EULA.
Manual Activation
Enables you to activate your copy of Unity offline. This is covered in more depth here.
Is something described here not working as you expect it to? It might be a Known Issue. Please check with the Issue Tracker at issuetracker.unity3d.com.
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