After installing the MD11 in FSX, it broke the 747. I lost the winglets, half the panel and the screens were blank. I re-installed the 747 and still the screens were blank, but got the panel and winglets back. So I thought I would check the MD11 and now those screens are blank too!!What I did notice after the MD11 install, it removed the pmdgoptions.dll from the modules directory. When I re-installed the 747 it put it back again.So is there a clash of dll's between the 747 and the MD11?Now I'm off to do another install of the MD11.Buzz.

Just an update. After re-installing both the 747 and the MD11 I've got the screens back in the MD11, but still not the 747. Getting very frustrating.What I did notice that the pmdgoptions module has remained in the modules directory this time.All very strange indeed.

pmdgoptions.dll is a common dynamic link library for both FSX versions. I assume you are using the installers to uninstall and you have tried the repair option.I am not aware of this being a reported problem before, but I'm not a part of PMDG. However, I would assume that the problem is with your system somehow... and if you could get to a clean FSX install with a valid dll.xml file, and if you have successful validation of the product then the install of either on top of other shouldn't be a problem. If the problem persists I recommend an email to pmdg support.

I'm suspecting the dll.xml file. Things may not be in the right order. I've tried repair functions on both. I have left the MD11 un-installed for now so I can fly the 747.

Ditto for me on this problem.Installed the MD-11x.747-400x has a blank main panel and the mini-icons are not clickable. PMDG menu is not available - nor does the FMC database load.MD-11 is fine.Uninstalled both. Reinstalled both - same result for 747.Ran "repair" on 747 - no luck.FSX / Vista 64 / Geforce 9800 GX2 / 680i SLI /4gb (2gbx2)Other add-ons = ASX and F.O.C

What finally fixed it for me was in this order. Deleted the dll.xml file. Deleted my fsx.cfg file. Uninstalled the 747 and the MD11.Started FSX and let it rebuild it's self. Changed all my options back to what they were.Then re-installed the 747 and the MD11. Now both work fine.I suspect between the fsx.cfg and the dll.xml files, I had a conflict somewhere.I must thank PMDG support as well.Buzz