How to Fix XmlSerializer error: Could not find file ‘C:\Users \….Temp \<>.dll’

A detailed Microsoft ‘apology’ is available here:    

The error is caused by the XmlSerializer and looks like this:
Could not find file 'C:\Users\Administrator\AppData\Local\Temp\1\<random numbers>.dll'

You may see this error in applications that run with your personal user account. It occurs because your user account may not have the necessary ‘full control’ permission on the temp folder and all subfolders.