That key also has the paths for V2 and V3 which are also correct as they were even though those versions are no longer installed.
THIS is a problem. It's not very clear if with "that key", you really mean *that* key, suggesting the Prepar3D v4\AppPath also has the paths for V2 and V3, which is clearly wrong, or you really meant to say "the similarly-named keys for the other two sims", which is ALSO wrong, if the two sims are no longer installer.
Because, it's entirely normal and correct the installer, which found a key for a sim, pointing to nothing (because it was uninstalled), would say it's incorrect, offering you a chance to point to the actual location of the installed sim (sometimes users make the mistake of "moving" the sim without updating the registry), which you cannot take, since there's no actual location anymore, since the sim is uninstalled.
The Add on Manager shows two tabs. one for P3Dv3 and the location is correct as was at that time, G:Lockheed Martin etc.
The tab for P3Dv4 shows D:Airports which is not correct
Please clarify this, because the Addon Manager is not supposed to have any tabs.
The file exists as my airports are in it but it is not within P3D. I cannot alter the entry.
As I've said, the entry is ready from the registry so, that's what your registry is REALLY pointing to.
The SODE platform manager shows the platform installation path correctly for V3 as was but the V4 path is again D:Airports
This CLEARLY confirm your problem doesn't have anything to do with our installer, or GSX, since even SODE is taking what you say it's the wrong location for the sim, which means your registry key is wrong, and you must fix it.
seems as though I want to completely remove it and start again but it looks as though it leaves debris when I use the uninstall.exe.
GSX doesn't leave "debris", and it has a proper uninstaller, which removes what is supposed to remove, which means only things related TO GSX. And it does an option to uninstall the Addon Manager at the end, which also remove all the supporting software, which is not obviously enabled by default, because all the other FSDT products depend on it, so it would just be wrong if Uninstalling GSX would always automatically removed *everything*
But that's not really the point. Regardless of the kind of GSX uninstall you choose, it's entirely irrelevant with your issue, which doesn't have anything to do with GSX or our installer or uninstaller.
Your issue is your some of your P3D registry keys are wrong, which is confirmed by SODE, saying the same thing so, unless you fix them, you are going to have problems with all of them.
This mess you have, LOOKS to be caused by using (or having used at time), the infamous Migration Tool, which screw up the registry entirely, in order to fool installers not recognizing P3D to install into it. Even if you don't use it anymore, the damage to registry would still be there, so you must fix it first.
It's this, or you did something really strange, like removing the sim (P3D V2 and V3) manually instead of uninstalling, because uninstalling them properly will surely result in their registry keys cleared up.
