Knowledge Base

Argument exception resulting from missing environment variable

Category: Installing & upgrading
Date: 10 Mar 2009
Product: all products
When installing a Red Gate product, the following exception may occur:

System.ArgumentNullException: Value cannot be null.
Parameter name: path1
  at System.IO.Path.Combine(String path1, String path2)...

When the installer extracts the files necessary to install a product, it needs to create a few temporary files in the system folder. The installer gets the location of this folder from the WINDIR environment variable. If this had not been set, the directory cannot be located.

By default, all Windows installations have this environment variable present. You may check for the presence of it by:

   · Right click the 'My Computer' icon and select Properties
   · Click the "advanced" tab, then the "Environment Variables" button
   · In the System Variables pane (usually the bottom one), look for the WINDIR property and ensure it points to the root Windows installation folder for the installation of Windows that you had booted into, for instance c:\windows.
   · If the directory is missing or invalid, correct it and save your changes. (The change may require a reboot)
   · The installer should then work correctly.