Installer: "Installation directory must be on a local hard drive" about snoopwpf

[batzen]

Does the installer prompt for elevation when you click "Install" or at which point during the installation does it show that error?

[mathdons]

Does the installer prompt for elevation when you click "Install" or at which point during the installation does it show that error?

It does not.

[batzen]

That's strange as it should prompt for elevation.
Could you try to run an elevated command prompt and start the MSI from there?

[mathdons]

Same thing from elevated cmd or PS, doesn't prompt, same message.

[batzen]

That makes no sense to me.
Could you run the installer with verbose logging enabled and attach the log here?
You can enable verbose logging by calling the installer from a command prompt using
msiexec /i Snoop.5.1.0.msi /L*vx "C:\ExampleLogFilename.txt"

[mathdons]

Sure, here it is, ran from elevated cmd.
msilog.txt

[batzen]

That looks like an bug in WiX/MSI itself as it's not even logging what failed during ValidatePath.
What's also strange is that ValidatePath returns 1 (success) but does not set WIXUI_INSTALLDIR_VALID to 1.

Maybe you can launch dbgview when running the installer as the installer should also output trace messages there.