Invalid MEX File rjpg8c.mexw32

April 7, 2015
January 7, 2016

Some users have been getting the following error:

Invalid MEX-file ‘C:\Program Files\MATLAB\R2013a\mcr\toolbox\matlab\imagesci\private\rjpg8c.mexw32′

Error in readjpg

If you are getting the error, updating to the latest release should solve the issue. If you are out of support and cannot run the latest version, we highly recommend renewing, however you can manually fix the issue.

Navigate to the Imatest installation folder (C:\Program Files\Imatest\v4.0\Master if you are using Master 4.0, replace with the version you are running) and right click on the run_imatest.bat file and select “Edit”. This should open the file in a text editor. Once you’ve done that, replace it with the following text, save and then retry Imatest.

@cd “C:\Program Files\Imatest\v4.0\Master”


@path=C:\Program Files\MATLAB\MATLAB Compiler Runtime\v81\bin\win32;%path%


@title Imatest DOS window

@echo Loading Imatest…

@imatest.exe -1 %1

If you continue experiencing issues, please email us at


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