Of all the add-ons I use, GSX is the only one that refused to install unless the regedit was tweaked to 'fake' a co-existence. I can confirm that it did indeed help get GSX installed
That's because not many other addons even *recognize* FSX:SE, so they don't even bother to check for the FSX:SE folders or the co-existance, so they will only work when FSX:SE is installed stand-alone, using the usual FSX registry keys.
GSX installer is a *PROPER* FSX:SE installer, so it checks for it BOTH in the FSX folders but ALSO in the FSX:SE-specific folders, and to be sure it's installed side-by-side, it also knows and check the co-existance registry key.
Maybe this wasn't entirely clear to you, so I'll explain it again:
1) If you install FSX:SE on a system with NO FSX, the folders and registry keys used will be the SAME AS FSX
2) If you install FSX:SE in a system WITH FSX, the folders and registry keys used will be the FSX:SE specific, AND the "co-existance" registry key will be set to 1
Your situation was not normal, because you had
- FSX:SE installed in the FSX:SE folders, which happens ONLY if you install it when an existing FSX is found, but you didn't had the co-existance key.
This situation LOOKS LIKE as if you installed FSX:SE when you HAD FSX installed, then you removed FSX, so the co-existance key was removed. But you said you "never" had FSX installed, so something doesn't add up.
I'll repeat it and confirm it again (especially since I JUST reinstalled Windows from scratch this week, and I installed ONLY FSX:SE on a brand new drive):
If you install FSX:SE on a clean system with no FSX, it will use the standard FSX registry keys, NOT the FSX:SE keys you have in your registry.
but having GSX installed has been very unstable with frequent crashes. Disabling or uninstalling GSX = everything back to normal, running smooth as buttah'
There are no crashes with FSX:SE that could be associated to GSX, and being sure of it "just" because the SEEMS to disappear by uninstalling, doesn't mean the crashes are *caused* by it.
GSX is simply discovering a problem that you HAVE, but cannot be disclosed without it.
You might have a problem with either your video settings, or your FSX settings, and this problem might appear ONLY if an object, which is an otherwise 100% legal object made according the SDK rules, has some material properties that no other add-on use, and they might not work because of a problem with either your settings or video driver, and this easily explains why you might be mislead thinking "it's a GSX problem, because it goes away if I uninstall it", when IT'S NOT.
Something that you might also check, is the use of the default "Screenshot" key in Steam. By default, Steam assign the F12 key to take screenshots, but there's no need to waste a key, since FSX has ITS OWN dedicated screenshot key ( the "V" key). But it's possible that, since Steam uses its own method to handle keypresses, the use of the F12 key MIGHT conflict with the key used by GSX by default, which contains the F12, but it's reserved and handled by GSX using the PROPER FSX method: which is Simconnect calls, that are entirely unaware of what Steam might be doing to the keys.
So, it might be safer to disable the screenshot key in Steam, under the "In Game" settings, and set it to "None". Also, it would be best if you disable Steam the in-game overlay too for FSX, because it might interfere with graphic objects.
Again, two example of issues that are not GSX "problems", but might be easily mislead you into thinking they are, just because the disappear when uninstalling GSX, without these being GSX faults, but simply because by removing GSX, you remove the chance for the conflict to appear, as in case of the Screenshot key, which you will not notice unless you install another addon that needs to use F12.
I'm giving GSX a pass until a proper FSX:SE fix is implemented, but I very much thank the developers for making a free demo available for us to test things out before purchase.
There's no need for any fix, and GSX is totally compatible with FSX:SE. And, thanks to the Demo, everybody can verify this is the case.