The App Paths directory search doesn't check that lightcraft.exe exists, and
when the old installers' unquoted path is gone, Windows Installer falls back
to the text before the first space: a deleted
C:\Program Files\LightCraft\lightcraft.exe resolved to C:\, so an upgrade
would install into the drive root. Gate the fallback on a second search of
the same value with a FileSearch for lightcraft.exe.
The install-folder test gains legacy-folder-deleted (failed before this fix)
and legacy-exe-deleted cases, and removes its empty parent registry key.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Fall back to the parent directory of the App Paths executable when an
older installer did not write InstallFolder. Keep explicit destinations
and the newer stored folder ahead of the legacy fallback.
Exercise the real MSI searches and actions with isolated per-user probes
on x64 and x86, including legacy paths with spaces and Unicode.
Co-Authored-By: GPT-6 Astra <noreply@openai.com>
