MATLAB: Do I receive License Manager Error -4

MATLAB

When I try to start MATLAB or use a toolbox, I receive the following error:
ERROR: License Manager Error -4
Maximum number of users for MATLAB reached. Try again later
What does this error mean and how can I resolve it?

Best Answer

This error indicates that all licenses are currently in use. This means that all of the keys for a particular product have been checked out from your license server. You will not be able to access a license for the product until another user has returned the license back to the pool.For information about the current licenses in use you can check with your License Administrator. Your License Administrator can check the usage of licenses by following the instructions below.
Windows:
1) Launch LMTOOLS, located within the $MATLAB\etc\win{32|64} ($MATLAB\flexlm for releases prior to 2010b). If lmtools.exe is not in that folder, see the related solution "Why are necessary license manager scripts missing from my license manager directory?" below.
2) Click the "Perform Status Enquiry" button on the SERVER STATUS tab to get a full report of the current license usage.
For Unix/Linux/Mac License Manager:
1) Open a terminal Window. For Mac OS X, use the Terminal application located in the Applications/Utilities directory.
2) In the terminal, change directories to the $MATLAB/etc directory. For example:
Linux
cd /usr/local/MATLAB_R2010b/etc
Mac OS X
cd /Applications/MATLAB_R2010b.app/etc
3) Run the following command to get the usage information
./lmstat -a -c license.dat
An example output from LMTOOLS or lmstat is located below:
--------
Status
--------
Flexible License Manager status on Mon 9/28/2009 15:35
[Detecting lmgrd processes...]
License server status: 27000@license1
    License file(s) on license1: C:\Program Files\MATLAB\R2009b\flexlm\license.dat:
 license1: license server UP (MASTER) v11.6
Vendor daemon status (on license1):
       MLM: UP v11.6
Feature usage info:
Users of MATLAB:  (Total of 2 licenses issued;  Total of 2 licenses in use)
 "MATLAB" v22, vendor: MLM
  nodelocked license, locked to "ID=123456"
    joesmith joe-pc joe-pc (v22) (joe-pc/27000 102), start Mon 9/28 15:37
    janedoe jane-pc jane-pc (v22) (jane-pc/27000 101) start Tues 9/29 08:26
In this example, a license would not be available until either Joe or Jane closes MATLAB to return the license.
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