PrepareOS

PrepareOS.ps1 prepares a Windows reference machine for image capture. It runs
standalone (ConfigMgr Capture Media or ad-hoc) or as a ConfigMgr/MECM Task
Sequence step, writes a CMTrace-compatible log, and drives the Task Sequence
progress dialog when one is present.

Optional parts (each controlled by a -Skip* switch):
 GPT        - GPT attribute check / remediation
 BitLocker  - Decrypt and verify all BitLocker volumes
 SCCM       - Remove the SCCM/ConfigMgr client
 Appx       - Remove non-provisioned Appx packages
 DISM       - ScanHealth / RestoreHealth / ComponentCleanup
 Sysprep    - Generalize and shut down via Sysprep

When running inside a Task Sequence the script calls
Microsoft.SMS.TSProgressUI.ShowActionProgress to reflect live progress.

AUTOMATIC SKIPS (v1.10.1)
-------------------------
The script resolves the effective -Skip* state before building the plan and
logs every automatic decision. Two independent mechanisms apply:

1) Task Sequence auto-skip
  When Microsoft.SMS.TSEnvironment is detected and the switch was NOT passed
  on the command line, the following are forced to $true:
    -SkipSCCM      ConfigMgr client removal belongs in a dedicated TS step;
                   removing the agent mid-TS kills the TS execution engine.
    -SkipSysprep   Sysprep belongs in a dedicated TS step (or the Capture
                   step) after this script has finished.
    -SkipRDP       Enhanced Session / RDP check is meaningless in Session 0.
  Any of these can still be forced ON inside a TS with the explicit
  colon syntax, e.g.  -SkipSCCM:$false

2) Platform capability guard
  -SkipBitLocker is forced to $true when the BitLocker feature/cmdlets are
  not present (default state on Windows Server - the previous behaviour
  raised a CommandNotFoundException).
  -SkipAppx is forced to $true on Windows Server (ProductType 2/3) and on
  any SKU where the Appx cmdlets are unavailable (e.g. Server Core), since
  Server SKUs are not supposed to carry Store packages.