Hi Tom:
If you have a working- or 'close to' working- build of your project, you could ZIP it / link it, and I'll take a look at it.
I personally wait at least 4 years after release before trying any new version of Windows, so I use Win-10.
Reportedly there are users successfully running FSX Acceleration on Win-11, so it is unlikely that version causing issues.
If you have the drive space, a FSX reinstall takes ~13 GB and 6 minutes to install on my (prior 3.8 GHz) computer.
FYI: I started in 1984 with DOS 2.0 on CompaQ portables and evolved through Windows 1.0 to modern desktops
I currently use:
AMD Ryzen 7 3700X 8-Core CPU @ 4.25 GHz, RX 5700 XT with 4 GB VRAM, 128 GB RAM, 15 TB M.2 / SATA SSDs
I used 'Teracopy' to more quickly copy all my FSX install CDs onto one of my SSD drives so the FSX install runs faster.
FS9 takes only 2 minutes to install.
I have numerous old backups of my FS9 and FSX install folder chains, and one each of "active" FS9 and FSX installs.
I also have "active" installs of P3Dv4.x, MSFS 2020 and MSFS 2024.
BTW: I also have old backup installs of FS8, FS7, and FS98 ...all of which still worked on Win-10.
Available drive space, install time, and patience are the only pertinent issues that may impact a FS reinstall.
Once FS add-on scenery packages are installed, they can be moved around and restored to use in "active" FS installs.
So, it is up to you as to whether you wish to re-install.
I have had to reinstall FSX
once due to a purchased faulty payware installer confusing FSX licensing code after 6 mo.
Other than that, MSFS has given me more problems than 2 decades of ACES older FS code ever did.
GaryGB