[wix-users] How to diagnose bootstrapper custom theme errors?

[Stephens, Rich]

I have a bootstrapper based on of WiXExtBa.  No custom code, just built the standard way, but with a customized theme file.
I recently made some minor changes, none of which I thought would cause any issues.  However, now, I get the classic "start, then immediately exit" issue with the error message in the log:

Error 0x80070490: Failed to initialize data in bootstrapper application.

In the past, this has been an issue with problems in the theme.xml file, but even with comparing it to the standard hyperlinklicensefile theme, I don't see anything immediately that would stand out.

Is there any way to diagnose what elements (or missing elements) in the theme file are causing the problem?

Rich Stephens