Ok.... Here is what I know. Everything FSDT related was working fine before I installed the update. I have uninstalled and re-installed the GSX add-on. Still doesn't work. I just landed at LAX this evening and my scenery is missing (FSDT KLAX). I've looked at everything you've suggested and none of it is fixing it.
I can only repeat and confirm what I said above, the problem are VC++ libraries in your system missing/corrupted.
May I please request that this get passed up and have someone look at it?
Maybe you haven't realized that I'm the one that made that program, so there's nobody else higher than that at FSDT, and yes, it has been looked at and, as I've said, there's no issue whatsoever with bglmanx.dll
There's no a SINGLE solution because, as I've said too, that error does NOT mean "this module has a problem", even if it SAYS SO. The real meaning is "I was unable to load this module for SOME REASON", and the reasons are countless, but you'll see only that message, so you are mislead thinking the module "must have a problem", because that's what the message says, and there's must be some kind of universal solution that might work, because the message you see it's always the same, so you think the *cause* it's the same, but it's not.
That's why we offer multiple solution to try, but we keep finding new causes, obviously none of them having anything to do with our software or that we can fix on our side, like the double copy of FSUIPC running, which was unique and never heard of until the last day.
An hint: NOBODY ever reported this problem with Prepar3D, and the bglmanx.dll ( Addon Manager ) is exactly the SAME, bit-by-bit, it's the same file so, it obviously doesn't have the problem in the first place, it's more like that LM has finally fixed the bogus error message.
If you contact me in private, we can arrange a Teamviewer session, so I can have a look at your system and see what's causing it in YOUR case.