---
name: windows-offline-dism-repair-gotchas
description: Windows won't-boot / offline DISM repair playbook — diagnose wedged-update boot loops, and the WinPE source/mount gotchas (wim: not allowed offline, Ventoy breaks WIM mount)
metadata:
  type: reference
---

Field-learned gotchas for repairing a Windows box that won't boot, from offline WinPE/recovery. First hit on Four Paws AvImark server (Syncro #32447, 2026-06-23) — boot-looping into Automatic Repair.

**1. Diagnose the REAL boot blocker before chasing DISM corruption.**
A machine that drops into **Automatic Repair** is failing on something boot-critical (disk, registry hive, boot files, or a wedged update) — NOT on shell/Search/appx component-store corruption. Component-store corruption in `ShellExperienceHost`/`StartMenuExperienceHost`/`windowssearchengine`/Cortana is a *symptom*, not the cause; repairing it does NOT fix the boot loop. Read the actual cause first: `C:\Windows\System32\LogFiles\Srt\SrtTrail.txt`, and run `chkdsk C: /f` (disk errors are the #1 Automatic Repair cause).

**2. `FaultyPackageInProgress` + hundreds of "Install/Uninstall Pending" packages = a wedged cumulative-update transaction.** That IS the boot blocker. Confirm offline with `dism /Image:C:\ /Get-Packages /Format:Table` — look for many `Install Pending` / `Uninstall Pending` lines at the same timestamp (a half-applied CU swapping old build -> new build). Try to back it out with `dism /Image:C:\ /Cleanup-Image /RevertPendingActions`, or WinRE -> Troubleshoot -> Advanced -> Uninstall Updates -> "Uninstall latest quality update". If RevertPendingActions FAILS and there's no `pending.xml`, the transaction is too corrupt to repair in place -> clean install.

**3. Offline DISM won't accept a `wim:` source (`0x800f082e CBS_E_NOT_ALLOWED_OFFLINE`).** For `/Image:C:\ /Cleanup-Image /RestoreHealth` you must **mount** the install.wim and point `/Source` at the mounted folder's `\Windows`, not use `/Source:WIM:...:idx`:
```
mkdir C:\wimmount
dism /Mount-Image /ImageFile:D:\sources\install.wim /Index:6 /MountDir:C:\wimmount /ReadOnly
dism /Image:C:\ /Cleanup-Image /RestoreHealth /Source:C:\wimmount\Windows /LimitAccess /ScratchDir:G:\scratch
dism /Unmount-Image /MountDir:C:\wimmount /Discard
```
Mount point must be an empty folder on a writable **NTFS local** drive (not the USB — Rufus UEFI sticks are FAT32 and hold the source itself). `0x800f0915` (repair content missing) usually means the offline backup store is gone and `/LimitAccess` blocked the WU fallback.

**4. Ventoy breaks WIM mounting (`0xc1420134` / "GetMountedImagesKey... file not found").** Ventoy serves the ISO through a virtual driver that also blocks `wim:` source access. Use a **Rufus**-built install stick instead — mounting then works.

**5. Build matters for the source: Win11 25H2 (build 26200) is 24H2 (build 26100) + enablement package; component store is 26100-versioned.** DISM matches on component version, not the marketing build, so the matching media for a 26200 box is a **24H2 / 26100 ISO**. Verify before repairing: `dism /Get-WimInfo /WimFile:<wim> /Index:6`.

Related: [[cyndyoffice-physical-hp-lockups]], [[feedback_rmm_system_context_mapped_drives]].