I'm having a similar issue. I recently updated to Windows 10, from Windows 8.1, which had been working. FSX continued to work for several days after that with some connection problems with some of the devices I use. Most notably, the Saitek Pro Trim Wheel seemed to conflict with my mouse and cause complete system crashes, even when not running FSX. So, I disconnected the trim wheel, but things continued to deteriorate to the point where FSX would load to the initial screen, but as soon as I hit Fly, it resulted in a CTD. After multiple attempts to fix this I began the slow process of a complete reinstall of FSX. After adding each new addon, I ran the simulation, which ran quite well after the initial installation from the box. It also ran after installing Active Sky Next. When I initially installed the latest version of FSUIPC, it worked the first time I loaded the game. All of my Saitek panels came to life, the switches were working, WooHoo!. Then I installed UTX, and tried to run FSX. I got the exact same CTD I had been getting before starting the reinstall Process. The error log is as follows:
Faulting application name: fsx.exe, version: 10.0.61637.0, time stamp: 0x46fadb14
Faulting module name: fsui.dll, version: 10.0.61637.0, time stamp: 0x46fadb59
Exception code: 0xc0000005
Fault offset: 0x0003d058
Faulting process id: 0x2300
Faulting application start time: 0x01d0ddcbf4f6c25c
Faulting application path: C:\FSX\fsx.exe
Faulting module path: C:\FSX\fsui.dll
Report Id: 5dae023f-49bf-11e5-bfe5-7845c4fe675c
Faulting package full name:
Faulting package-relative application ID:
I've since tried uninstalling UTX, no change, I removed the module folder for FSUIPC, no change, I tried the above mentioned fix, as I had also inadvertently installed the loader, this also did no good. I'm out of ideas, except for starting over, and maybe skipping UTX, and making sure I don't use the loader.dll. Would appreciate any thoughts you have before starting that again.