-Customization times out majorly due to following reasons. Please check below services are working fine:

• DNS issue.
• DHCP issues as machines do not get a valid IP.
• Check if machines are getting joined to domain or not.User account used for linked clone operation does not have sufficient permission to join machine in domain. Check Create a User Account for View Composer AD Operations
• License activation issues (Skip license activation through registry on master image and test : VMware Knowledge Base )
• Issue with Sysprep script if you are using sysprep instead of quickprep.
• If you are using quickprep for guest customization, provide the below log from the linked clone VM where you see 'customization timed out':

   %system_drive%\Windows\Temp\VMware\vmware-viewcomposer-ga-new.log