Forum Discussion
Rachi
Feb 18, 2026Copper Contributor
Installing Windows server 2025 is failing with this error.
when booted from Winpe and triggered installation of Windows server 2025 OS install it is failing. Can anyone helps with this. below is the error. 2026-02-18 14:10:04, Error CDiagnosticsHelper::P...
Charlie34000
Apr 03, 2026MCT
Hi,
The errors in your setup logs point to an issue with the WinPE environment or the target volume, not with Windows Server 2025 itself.
The repeated failures:
- Access is denied on E:\$WINDOWS.~BT\Sources\Diagnostics
- 0x8007000D (invalid data)
- 0xC06D007E during offline sysprep
- inability to create folders under $WINDOWS.~BT
all indicate that the target drive is not writable during setup.
✔️ 1. Check if the target volume is read‑only
In WinPE:
diskpart
list volume
select volume X
attributes volumeIf Read‑only : Yes, clear it:
attributes volume clear readonly✔️ 2. Make sure you are not installing to the USB/ISO media
In WinPE, drive letters often shift.
Confirm that E: is really the internal disk and not the installation media.
✔️ 3. Reformat the target partition
If the $WINDOWS.~BT folder already exists or is corrupted:
format E: /fs:ntfs /q(or delete/recreate the partition in Diskpart)
✔️ 4. Try a clean WinPE
Some custom WinPE builds block writes to secondary volumes.
Using the stock ADK WinPE usually fixes this.
If you can share the output of diskpart list disk and list volume, I can help confirm the correct target drive.