1. Your system may have gone into 'Sleep' mode during the download process.
Check the power settings on your system. If you walked away from your system during the installation, and your computer went into 'sleep' mode, this will disrupt the process and you will not be able to continue with the installation without completely stopping it and then starting the installer again. The installer is designed to prevent the system from going into 'sleep' mode, but some systems may still go into 'sleep' mode if you are not interacting with the system for a long period of time while the installer is running.
2. You receive an Unexpected or Unknown error installing a toolbox into an existing installation.
If the pathdef.m was manually modified or edited this error may occur during the download portion of the installation regardless of using the downloaded installation files or installer. Run the following commands in MATLAB then try the installation again: