Error upgrading to current release - "failed due to powershell.exe.config" (4324906)

Event Log reported the following: "Product: Binary Tree Migrator Pro for Exchange. The application tried to install a more recent version of the protected Windows file C:\Windows\system32\WindowsPowerShell\v1.0\powershell.exe.config.  You may need to update your operating system for this application to work correctly. (Package Version: , Operating System Protected Version: )."

What is causing this?

The error is actually unrelated to the powershell.exe.config file

A review of the installation log will show there was a failure while trying to update/install the Migrator Pro for Exchange website.

CustomAction ISIISInstall returned actual error code 1603

After this had failed, it looks like it rolled back the install, thus attempting to revert the changes made. We think the PowerShell error is just some oddity in the rollback.

The real cause resulted during the rollback, were the website installation failed. Something has become corrupt with IIS requiring a reinstall of  IIS. We were unable to determine the the exact role feature as this was not reproducible in our labs and only seen on one client site.

Perform the following steps:

1. Open IIS from Server Manager
2. Remove the entire web server role, .net HTTP activation, and windows process activation in order to bring IIS back to a default state.
3. Reboot
4. Re-install the required roles and features (or let the installer do it)
5. Run the Binary Tree Migrator Pro for Exchange setup installation