When trying to provision a VM from a template, this error is thrown “Action =unknown action, The formatter threw an exception while trying to deserializethe message: There was an error while trying to deserialize parameter http://ProvisionNetworks.BrokerHelper:sysprepText.The inner exception………"
The Maximum String Content Length is controlled by a Web.Config file.
In our case, you can find this on your SCVMM server under C:\Windows\System32 in a file called pnbrkhlpsvc.exe.config
1. Take a backup of pnbrkhlpsvc.exe.config
2. Edit the binding section and add the extra line you'll see in my screenshot
3. Restart the service Quest Broker Helper Service