Buyer beware: TurboTax and .Net apparently do not get along

It's tax season, which is not something that I ever write about on this blog. But this year, I had a very irregular experience. It wasn't with my taxes; rather, it was with my dad's attempts to use this year's TurboTax software. He'd been using TurboTax for years with no problem, but this year, the program wouldn't install. He's not exactly tech-savvy, so he had to call me to help him troubleshoot.

TurboTax fails to install due to some unspecified issue with the .NET Framework.

Upon attempting to install the program, he gets a very un-descriptive error message that simply states there was a problem installing TurboTax. Then a dialogue pops up stating that TurboTax is attempting to fix the problem by checking the file system, registry, and .Net framework. It's the .Net Framework step where TurboTax fails with yet another very un-specific error.

We tried updating Windows, disabling anti-virus software, and even opened up the registry to make sure that all the requisite versions of .Net Framework were installed. No luck.

Unable to resolve the problem itself, TurboTax referred us to a troubleshooting web page.

TurboTax referred us to this troubleshooting page, which includes instructions for downloading and running various .Net Framework repair tools and other system file integrity tools. In my dad's case, none of this stuff worked. As a last resort, the troubleshooting guide referred me to a blog post by Microsoft developer Aaron Stebner, who wrote about a .Net Framework cleanup tool that could potentially be used to resolve the issue...