How to generate a Machine Key in IIS Manager

To generate the machine key first you will need to connect to your site using IIS Manager:

 

Once connected double click on the Machine Key Module

 

 

 

On this page click "Generate Keys" on the right side of the screen. Note the boxes for "Automatically generate at runtime" will be unchecked.

 

 

 

Once the keys have been generated click on Apply in the top right:

 

 

You can find the newly generated key in your web.config:

 

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <system.web>
          <machineKey decryptionKey="###############,IsolateApps"                               validationKey="############,IsolateApps" />
    </system.web>
</configuration>