Installing Windows 8.1

[Arjay]

John, 2kaud. With regard to upgrading... As I mentioned, it's a real hit and miss for apps to work post upgrade given all the factors (tightened security, accessed reg keys, file locations and so on).

While Microsoft does extensive testing for upgrade scenarios (they have a complete App Experience team dedicated to it), they can't possibly cover all apps under all scenarios. For the tops apps they go out of their way to make sure the apps work after migration. When problems are encountered they shim the app when possible, and will contact the 3rd party App OEM to let them know their problem. Sometimes the oem is responsive and will create a patch for the app or fix the issue in a newer version of the app. Other times the oem completely ignores MS and does nothing to fix the app. Of course, MS gets the blame for the bad app, not the 3rd party.

I mentioned that I worked in this team years ago and we extensively tested the top few hundred apps (and had thorough test automation that tested the top 100 apps).

At that time, there was no way we could test some [unknown] oem vendor that had a user base of 2. While I bet that the top app base has increased since when I worked there (guessing maybe up to 250-300 top apps at present), there still is no way that MS can test the 10's of thousand of OEM apps out there for each upgrade scenario.

For most of these OEM apps to work is pretty amazing considering the factors involved, but the best chance of this is when the OEM follows the App Compatibility Guidelines, understand the security model, how to classify and store app data, shared data, where to install the app, etc.

I see many folks post questions here on trying to hack the install locations or to store data in HKLM without elevating UAC and it just makes me cringe because I know that is going to be another 3rd party app that will fail an upgrade scenario.

App compat is something MS takes seriously, but it's definitely a dilemma: should MS not make security improvements and bug fixes that could potentially break existing apps; or should they make them and potentially break the apps that are not in their testing matrix?

No matter which direction is taken, someone is going to not be happy. I'm guessing that Microsoft has taken the approach of making the OS more secure (which is the correct decision, imo).

Because of all these factors, I believe the recommendation is to clean install the OS and the apps. When this isn't a possibility, a new option may be to turn the existing OS install into a vhd and run it on a host machine as a vm.

Good luck to both of you in your upgrade scenarios.

P.S. If you have problems upgrading, call 1.8MY.APP.SUC3

Disclaimer: As before, even though I'm an MVP, my opinions are my own.