QWT installer prepare-volume broken on Windows 10 HVM

[historicbruno]

Qubes OS version
R4.0 (4.0.1)

Affected component(s) or functionality
QWT installer (prepare-volume.exe)

Brief summary
QWT installer runs prepare-volume.exe to initialize and format the private.img disk for user profiles. In a Windows 10 Pro HVM, the format fails with an unknown error (not documented by MS). The problem is InitializeDisk creates a broken disk layout.

To Reproduce

1. Run QWT installer in Windows 10 Pro HVM
2. Use "move user profiles" option (default)
3. Proceed with installation
4. prepare-volume.exe fails with an unknown FormatEx error

Expected behavior
QWT installer should complete successfully, leaving a properly formatted X:\ drive.

Actual behavior
X:\ is left in a broken state, not even Windows format utility can fix it.

Additional context
Using a secondary disk pool for my Win10 HVM. Fully updated "clean" install of Win10 Pro 1809.

Solutions you've tried
There is a workaround, if the user manually formats the X:\ drive prior to running the installer. However, prepare-volume can easily be fixed (see pull request).

Related
QubesOS/qubes-core-agent-windows/pull/4
#1861

[github-actions]

This issue is being closed because:

• This issue is on the "Release 4.0 updates" milestone.
• Qubes OS 4.0 reached EOL (end-of-life) over one year ago.
• There has not been any activity on this issue in over one year.

If anyone believes that this issue should be reopened and reassigned to an active milestone, please leave a brief comment.
(For example, if a bug still affects Qubes OS 4.1, then the comment "Affects 4.1" will suffice.)