When updating a catalog the below error is seen when 'More Details' is selected:
This machine catalog has the following warnings:
An error occurred while creating the virtual machine.
Stack Trace: at Citrix.Orchestration.Base.PowerShellSdk.ProvisioningSchemeService.BackgroundTask Unable to add machine to an existing MCS catalog.
Error seen : An error occurred while creating the virtual machine.
DesktopStudio_ErrorId : ProvisioningTaskError ErrorCategory : NotSpecified ErrorID : LocatingResources InternalErrorMessage : NotEnoughCoresInRegionNoCoresInfo
The error InternalErrorMessage : NotEnoughCoresInRegionNoCoresInfo indicates there are no more available vCPU (virtual CPU) cores for the Azure subscription used for the MCS catalog.
Managing Azure limits and quotas for Citrix workloads
https://dennisspan.com/managing-azure-limits-and-quotas-for-citrix-workloads/
Additional Microsoft online reference for querying the vCPU allocation for an AzureRM subscription;
https://docs.microsoft.com/en-us/azure/virtual-machines/windows/quotas#