I read some folks were having to reinstall FS9 after installing PMDG 747X, but I may be mistaken.Until I get a decent computer for FSX I will be sticking with FS9 but wanted to buy to 747X with FS 9 upgrade while the upgrade price is still around.How prevalent is the issue of damaging Fs9 with 747X, or is it just reinstalling the 747? I prefer not to risk either of courseThanksGreg

Greg-it's not the installation of the PMDG 747X that breaks your FS9 install. It's the FSX installation that might do that. The problem is that the FSX installation sometimes screws up the registry keys for FS9.However, there's a simple fix that you can find if you look at the pinned topic at the top "Message saying FS9 Installation not found". You'll find a utility that takes care of this issue.Best regards,

Thanks fof the clarification! Now I feel OK with getting the new version.I have found the pinned topic you mention.Greg