If you imported a newer Windows Server 2025 release into MDT, you have probably seen this message when trying to deploy it:
No task sequences are available (TaskSequences.xml does not exist, is empty, or is inaccessible)
A VBScript Runtime Error has occurred:
Error: 6 = Overflow
VBScript Code:
InitializeTSList
Reason for the issue
It turns out that newer versions of Windows Server 2025 have a quite high Update Build Revision (UBR) number. For example, the May 2026 Windows Server 2025 media has a UBR value of 32860 (the full version is 10.0.26100.32860).
The number 32860 exceeds VBScript's signed 16-bit Integer (CInt) ceiling of 32767 by 93, and the GetMajorMinorVersion function in the ZTIUtility.vbs script is hardcoded to use CInt.
Temporary Workaround
As a quick workaround, after importing the operating system image, simply change the UBR value to a value of 32767 or lower.
Longterm Fix
A better long-term fix is to modify the ZTIUtility.vbs script to support higher numbers (make a backup first). Replace CInt for CLng on all seven conversions in that function (lines 1617, 1620, 1621, 1623, 1624, 1625, 1631). CLng handles up to 2,147,483,647, which retires this permanently.
Leave the 32767 sentinels at lines 1627-1629 and 1633-1636 alone. They're just "unparseable version" markers, and any code comparing against them still works fine once the parsed values are Longs.
Then update the deployment share and regenerate the boot image so WinPE gets the patched script.
Here is an already updated version: https://github.com/DeploymentResearch/DRFiles/blob/master/Scripts/MDT/ZTIUtility.vbs
Final tip!
Please note that Windows Server 2025 does not support the Microsoft-Windows-SystemRestore-Main component, which is the default in the MDT template. So, make sure to remove that from the unattend.xml used in your Windows Server 2025 task sequences.
Hi! Thx for this! It is now working again even with newer builds! 🙂 We are using SkipWizard YES and TaskSequendeID value populated in different MDT Roles so the Task sequence starts silently. In case someone has the same error I will post the error here:
Failed to run the action: Validate.
The handle is invalid. (Error: 00000006; Source: Windows) TSManager 2026-08-21 15:08:16 380 (0x017C)
And to clarify, it is now working again with your patched ZTIUtility.vbs! Thx alot! 🙂
The errorcode was almost the same! I guess the validate step also uses the ZTIUtility.vbs
Thanks for sharing!