The MATLAB installer will fail to detect an existing installation if the permissions on the machine prevent it from properly reading and writing to the installation directory. If running the installation as a standard user account fails, run the installer with the sudo command to install as root. This can be done with the following commands in the terminal:
sudo /Volumes/matlab_R20XXx_maci64/InstallForMacOSX.app/Contents/MacOS/InstallForMacOSX
on Mac machines
or
sudo /path/to/installation/folder/install.sh
on Linux machines.
If you are unable to resolve the issues with installation, please contact MathWorks Licensing and Installation Support for further assistance.
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