This article explains how to fix the "Activation failed: serial number has reached maximum license activations" error in Unity Hub. This typically happens when a license is already active on two devices or after hardware or OS changes that invalidate the license file. It walks users through releasing activations via the Unity Dashboard or manually deleting the outdated license file. These steps help ensure a clean reactivation so users can regain access to Unity without further interruption. ✨
Cause:
Unity licenses are intended for individual use and can be active on up to two personal devices at a time.
If you encounter a "maximum license activation" error, it usually means that both of your allowed activations are already in use. To resolve this, you’ll need to free up a license by deactivating it from one of your current machines. In some cases, this issue 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.
Occasionally, you might notice what appears to be two activations on the same machine, one listed with an "Entitlement" tag and another associated with 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, which are typically used with Industry, Enterprise, and Pro plans, are linked directly to your Unity ID once a license seat has been assigned. This system does not require a serial key. Activation occurs automatically when you sign in to Unity Hub, and deactivation happens when you sign out, making it simple to switch between devices.
In contrast, Serial-based licenses activate using a serial key, either through Unity Hub or via the command line. While this method is considered legacy, some users still prefer it in specific scenarios, such as automated build environments or manual activations on offline machines.
Resolution:
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 Industry/ Pro/ Enterprise license?'
If releasing your activations and checking your connection still do not help you activate your license, 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 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
and delete the .ulf file housed there (folders are usually hidden).
Relaunch the Hub, making sure you allow the Hub 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?
If your license is still not activating after troubleshooting, get in touch with Customer Experience, including your Hub log file in your ticket, so we can look closer at your issue.