> ...the C:\WINDOWS\Installer\MSI9D2C.tmp-\ folder is not created on disk.
Yes indeed it does look like a SFXCA problem. If you really want to get at the bottom of it you may want to log the defect at WiX wiki. The easiest way to do this is to call BuildMsiCmd and this will produce a batch file that will only use WiX tools and your wxs sources. This way your test case will not be polluted with Wix# logic and this WiX friendlier version will be easier to deal with for the WiX guys.
> I mention that all temporary folders created for running the normal custom actions, before presssing Cancel button, exist on disk.
I am not sure it is true. I have observed very different behavier. WiX SFXCA runtime creates a fully self sufficient temporary dir for every single CA even if the action is using the same set of dlls.
Yes indeed it does look like a SFXCA problem. If you really want to get at the bottom of it you may want to log the defect at WiX wiki. The easiest way to do this is to call BuildMsiCmd and this will produce a batch file that will only use WiX tools and your wxs sources. This way your test case will not be polluted with Wix# logic and this WiX friendlier version will be easier to deal with for the WiX guys.
> I mention that all temporary folders created for running the normal custom actions, before presssing Cancel button, exist on disk.
I am not sure it is true. I have observed very different behavier. WiX SFXCA runtime creates a fully self sufficient temporary dir for every single CA even if the action is using the same set of dlls.