Linux LEGO Mindstorms EV3 USB Connection Problems

I cannot connect my LEGO Mindstorm EV3 with MATLAB. I always get this error message:

Error using error
Unable to load a message catalog 'legoev3io:build'. Please check the file location and format.

Error in legoev3 (line 157)
                                error(message('legoev3io:build:CommInvalidType'));

When I use MATLAB as a root user (which only works when I deactivate my license and activate is with the username "root"), it connects more or less easily. However, I do not want to use MATLAB as a root user, since it forces me to enter my root password everytime I use MATLAB. I use MATLAB as a student to program econometric models and simulations and never had a problem that could be solved licensing MATLAB as root user.

Answer 1

[Walter Roberson]

The most common reason for being unable to load a message catalog is that the user has too many files open, such as if the user has an fopen() in a loop that has no fclose(). There have been some versions in which the MATLAB internal code for save() or xlswrite() have been at fault: if you have an older version and have either of those in a loop then you could run out of file descriptors.

If you are using linux then you might need to modify the process limits, what is reported with ulimit -n . However the default is 1024 for Linux which should be enough if you are not leaking file descriptors.

If you are using MS Windows, the default limit might be much much smaller, as low as 10 in very old versions of MS DOS.

[Ulrich]

Thank you for your suggestion. However, I have no files open, I am not even running a script, yet. I just start MATLAB after my computer booted, and put in the command

EV3 = legoev3('USB') ;

(or similar, with 'usb'). So, I am pretty sure the problem your are describing is different from my situation. I also want to point out that it works when I run MATLAB as an administrator!

[Walter Roberson]

I wonder if the file is for some reason not readable to ordinary users?

I do not know which file type Mathworks uses for message catalogues so unfortunately I have no suggestions about where to look. Other than that I know that on MS Windows support packages are installed under C:\MATLAB\