Today I was trying to deploy an ARM template with Test-AzureRmResourceGroupDeployment and New-AzureRmResourceGroupDeployment and received the following error:
The template deployment GUID is not valid according to the validation procedure. The tracking id is GUID. See inner errors for details.
Getting the error details
You can pull the error out using PowerShell really easily:
Get-AzureRMLog -CorrelationId <GUID> -DetailedOutput