# How to perform a clean installation?

## How to do a clean installation?

1. Remove or uninstall any previous or existing installation of the simulation tool or the FlexNet license manager (depending on which one you are planning to install).
1. Delete the installation folders from your machine. (default install locations shown below).
Windows:
Delete the appropriate folder found in: C:\Program Files\Lumerical\

Linux:
Delete the appropriate folder found in: /opt/lumerical/

2. Remove the preference files as based on the locations indicated on our KB:
https://kb.lumerical.com/install_config-preference-file.html

Note: the user preference files are hidden on Windows, Unhide first to delete..

Enter the path: %appdata%\Lumerical on your explorer address bar.

Note: System wide preference files might not be automatically created, if this is not found skip this process.