There are two options for customizing instant clone virtual machines: VMware ClonePrep or Microsoft Sysprep.

ClonePrep is a VMware customization process run during instant clone deployment to personalize each desktop clone created from the parent image. During the initial startup of each desktop, ClonePrep:
  • Creates a new computer account in Active Directory for each desktop.
  • Gives the instant clone desktop a new name.
  • Joins the desktop to the appropriate domain.

Sysprep is a Microsoft tool to deploy the configured operation system installation from a base image. The desktop can then be customized based on an answer script. Sysprep can modify a larger number of configurable parameters than ClonePrep, but ClonePrep is significantly faster. Majority of instant clone customers choose ClonePrep

The following table lists the main differences between ClonePrep and Sysprep:
Function ClonePrep Sysprep
Removing local accounts No Yes
Changing Security Identifiers (SID) No Yes
Removing parent from domain No Yes
Changing computer name Yes Yes
Joining the new instance to the domain Yes Yes
Generating new SID No Yes
Language, regional settings, date, and time customization No Yes
Number of reboots 0 2
Requires configuration file and Sysprep No Yes
KMS license activation Yes No (performed by Agent)
Post customization script, pre-shutdown script Yes No

It is recommended that you use ClonePrep unless there are specific Sysprep capabilities required for your environment.

For instant clones and ClonePrep, the table below shows the effect of various operations on SIDs.
Creation Push Image On User Logout
ClonePrep Parent Image's SID are used for the desktops SIDs are preserved unless parent image is changed SIDs are preserved unless parent image is changed