Unity licenses allow activation on two machines simultaneously; a "maximum license activation" error means both activations are in use or hardware changes invalidated the license file. To fix, return an activation via Unity Dashboard or delete the .ulf license file and reactivate through Unity Hub. Unity supports Named User Licenses linked to Unity ID and serial-based licenses using keys. Contact Unity Customer Experience with logs if issues persist.
Cause:
Unity licenses can be activated on up to two machines at the same time, but you may encounter a "maximum license activation" error, which means that both of your activations are already in use.
In some cases, this may also occur after updating your operating system or making hardware changes, as these can alter the hardware ID linked to your Unity License File (.ULF), rendering the existing file invalid.
Resolution:
To resolve this, you will need to return an activation from one of your current machines.
You can return activations made in Unity Editor versions 4.5 and higher via your Unity Dashboard. For instructions, see the article 'How do I return the activations on my Pro/Industry/Enterprise license?'
If releasing your activations does not solve the problem, you may be experiencing a conflict with the license file saved on your machine. To fix this, simply delete the current license file and reactivate your license through Unity Hub:
Close the Unity Hub completely using the task manager or similar.
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Using your file explorer, navigate to:
Windows:
C:ProgramData/UnityMac:
Library/Application Support/Unity
Delete the .ulf file here (The folders may be hidden by default).
Relaunch the Unity Hub, making sure you allow it to make changes to your hard drive in the process.
Reactivate your license following the steps outlined in the article, 'How do I activate my license?
You might notice what appears to be two activations on the same machine, one listed with an "Entitlement" tag and another listed as a serial key. This happens because Unity supports two different licensing systems: the newer Named User Licenses (NUL) and the older serial-based license model.
Named User Licenses:
- Typically used with Unity Pro, Industry and Enterprise plans. This is linked directly to your Unity ID once a license seat has been assigned.
- No serial key required.
- Activation is automatic when you sign in to Unity Hub, and is deactivated when you sign out again.
Serial-based licenses:
- Activated using a serial key, either through Unity Hub or via the command line.
- Legacy activation method. Preferred for automated build environments and manual activations on offline machines.
If your license is still not activating after troubleshooting, get in touch with Unity Customer Experience, including your Unity log files in your ticket, so we can resolve your issue. Your log files can be found here, 'I have been asked to provide a log file. Where do I find this?'