Anyone who works with Citrix Provisioning Services (PVS) is familiar with this challenge: The imaging process itself is anything but trivial. Creating a vDisk requires extensive preparation—boot order, BDM or PXE settings, and the correct sequence of sealing, capturing, and assigning. Each of these steps is prone to errors, and even once the process is set up correctly, the ongoing effort remains: mounting the vDisk, booting the target, capturing the image, and verifying it. None of this is something you can just do on the side.
Over the years, this cumbersome process has given rise to a behavior that can be observed among a large number of PVS administrators—and which I deliberately refer to as a Escape Name: The Escape into Difference Updates.
What the Escape Looks Like
It’s an understandable reflex. Once I’ve created a vDisk, I can start it in Private Mode and apply updates directly—or I can work with version and differential disks to simulate scenarios like maintenance and production. At first glance, it’s elegant: no need to re-image, no need to touch the master target—just update the existing disk.
The price, however, is high, and it often doesn't become apparent until later.
Why this is a fallacy
The Master Target isn't keeping up. As soon as the vDisk is further developed in private mode, it becomes decoupled from its own template. The original master target from which the vDisk was created is no longer in use—at some point, it will no longer match the version actually running in production. This means you lose exactly what makes PVS so valuable: a clean, reproducible reference.
Private mode is dangerous. Starting a disk in Private Mode carries real risks. If it accidentally runs in the wrong OU, on the wrong server, or with the wrong assignment, it will apply Group Policy settings that it should never apply. The vDisk’s integrity—clean, controlled, and free of production-related clutter—is then compromised.
This isn’t just a theoretical concern. It is precisely this pattern that has led to massive problems for customers: At some point, the image could no longer be used properly, showed anomalies—and ultimately required a time-consuming reverse/rematching process. The merged vDisk had to be converted back into a physical disk, and the entire process had to be undone. A huge effort. And all of this just to avoid the cumbersome process of using the Citrix Imaging Wizard. An attempt to escape the hassle that ends up leading to even more work.
This is where PVS Forge comes in
PVS Forge doesn't need to take this approach.
We keep the vDisk constant. We keep the master target constant. The Master Target is and remains our template—the ultimate standard. It is not distorted in private mode, but remains the pure source of truth.
Not re-imaging in the traditional sense. Instead of updating an existing disk, PVS Forge creates new vDisks—fresh and in a clean state, derived from the constant template. And if something were to actually go wrong on the master target, the customer can fall back on their hypervisor snapshots and roll back. So we always work with the clean template—not with a private-mode construct that has evolved over generations.
This eliminates all the hassle involved in creating vDisks, which was the very reason we turned to differential updates in the first place.
More Than Just Imaging: The Complete Lifecycle
PVS Forge doesn't stop at creation. With the Lifecycle Management it is possible to verify which version, build, and software version is in use—traceability instead of gut feelings. And with AI Support We can also flag problems before they become a hindrance to productivity.
This gives this method of creating vDisks a complete, end-to-end lifecycle—and is a much better solution than dealing with differential disks and private mode.
Even the two arguments that are often cited in favor of difference discs no longer hold water: The Installing Windows Updates and the execution your own custom scripts is no problem with PVS Forge. And in the future version with the Patch Day — which automatically installs Windows updates and automatically mounts a vDisk — this entire use case is seamlessly integrated into the product.
Conclusion
PVS’s differential update technique is, at its core, a stopgap solution—a way to avoid an overly cumbersome imaging process that, in practice, creates its own, often more expensive problems. PVS Forge eliminates the need for this workaround: a consistent master target, clean vDisks at the click of a button, and a complete lifecycle with traceability and AI support.
PVS Forge is the new way—instead of differential disks, which are really much too cumbersome.
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