Why do I see a "MathWorks License Update Required" message when I open MATLAB?

When opening MATLAB, I see the following message:

ERROR: MathWorks License Update Required
The licenses listed below are out-of-date. You should update these licenses.
This process overwrites your existing license file with the most current one in the MathWorks systems. 
This process contacts the MathWorks website via the Internet to exchange license data.

Why does this message appear?

Answer 1

[MathWorks Support Team]

This message will appear if changes have been made to your MATLAB license and the local MATLAB license file on your computer does not reflect those changes yet. You can proceed past this message by clicking the "Update" button and following the prompts that then appear. 

If the update button is unresponsive, then reactivating your license should resolve this error.

How do I activate MATLAB?

https://www.mathworks.com/matlabcentral/answers/99457-how-do-i-activate-matlab-or-other-mathworks-products

How do I activate MATLAB without an internet connection?

https://www.mathworks.com/matlabcentral/answers/259627-how-do-i-activate-matlab-or-other-mathworks-products-without-an-internet-connection

[Walter Roberson]

@Steven : this might turn out to be irrelevant to your situation, but since you asked what else can cause the user to get the message:

One way that it can happen is that license admins can attach expiration dates to generated licenses; provided that the admin later extends the license, the appropriate user action is to Update the license file.

This is not expiration of the license itself (such as might be the case for term licenses), this is expiration of the license file.

For example in Total Academic Headcount situations, because the payment is according to headcounts, you do not want to leave student licenses active for years at a time when they are not being used, so you might attach (say) 1 year expiration to a key generated for a student. As long as they update the license file at least once a year (in this hypothetical situation) then you know they are still active; if it expires and they are still around, they are inconvenienced a little but not much; if it expires and they are not around anymore, your license count doesn't explode with each new wave of students.

[Walter Roberson]

I do not recall ever having read about Validate before

https://www.mathworks.com/matlabcentral/answers/95643-what-is-validation-and-how-does-validation-work