Why do I receive MathWorks Licensing Error 21?

Why do I receive the following error:

MathWorks Licensing Error 21

Unable to find a license for this release of <PRODUCTNAME>.

Activate your license to get a new license file.

Answer 1

[MathWorks Support Team]

This error occurs when attempting to launch MATLAB with a license file that was generated for an older release. See the information below in order to resolve this issue:

Network based licenses

This error can occur when the version of MATLAB is newer than the version of the license file (license.dat) used by the Network license Manager. To resolve this issue, update the license.dat file and/or license manager on the license manager machine to the latest release that you are licensed for. If there are multiple license files on your machine, make sure it is pointing to the correct one. Contact your license administrator to make the updates.

The license.dat file on the server machine is located in:

$MATLABROOT/etc

Where $MATLAB is the MATLAB installation directory. You must stop the Network License Manager prior to changing the license file. The re-read license button will not work.

The network.lic file on the client machine is located in:

Windows

$MATLABROOT\bin\win64

Linux & Mac

$MATLABROOT/etc

Where $MATLABROOT is the MATLAB installation directory.

Individual and Designated Computer licenses

If you are receiving this error on standalone installation of MATLAB and have attempted to install from downloaded file, then this error may occur if you have multiple versions of MATLAB downloaded into the same folder. The workaround for this issue is to uninstall and reinstall using fresh downloads.