I just downloaded the update through the Operation Center, and afterwards it said there were livery data or something not found.
Then I selected the option to delete these textures, and when I restarted everything of the 777-200LR was gone. I only have the -200F and -300ER.

I can't select it in the Livery Manager nor in Livery Downloader.

The 777-200LR folder is still in the Airplanes folder in FSX, but without all liveries and when I open the aircraft.cfg file, the file is empty.

I would try downloading the update from the PMDG website and running that.

 

Otherwise, I would suggest contacting PMDG directly through the support system to see if they could send you a new aircraft.cfg file or otherwise help you fix your problem.

Same happened to me.  Next day I opened the OC and I had a notification that some AC were missing, asked if I wanted to restore them and I did got all the 200's back.

 

Gnacino

Same here. After the update to SP1b, I noticed two things...

1. All of my custom internal and external views had been replaced in the aircraft.cfg files with the default views.
2. All of my -200LR airline repaints were gone from the FSX Free Flight list; only the PMDG house colors remained. Strangely, my -200F and -300ER repaints were fine.

On a hunch, I opened the Operations Center to see if there were any messages. Lo and behold, there was just such a message waiting for me that said something like "we have detected that some liveries have been deleted". (I can't remember the specific wording.) When I ok'd the software to replace those missing liveries, they were all back within a few seconds. The custom views were not replaced, however. Since I've been down this road a few times before, I had my custom views saved to a separate, read-only file so it only took a couple of minutes to re-install them in all 3 aircraft.

 

Lessons learned...

• If any changes have been made to the aircraft.cfg files (e.g. custom views, Shockwave lights, edited exits, etc.), keep backup, read-only copies in a separate folder. This is especially important before starting any upgrade because there might not be any warning about replacing edited version with a default version. (I learned this one with other aircraft.)
• Check the PMDG Ops Center every few days. You never know what might be waiting for you.

PMDG should have forewarned that the ac config would be replaced.  I also had things backed up, so no biggy.  I haven't been flying any other ac since I got it last year.

 

Gnacino

 

 

PMDG should have forewarned that the ac config would be replaced.

Given that they pushed an "update", in my mind it's common sense that things like .cfg files, around which the whole add-on is pretty much built, would be edited.