Same issue when using the x64 version & outputting directly to the base drive as opposed to the mods folder in my MO2 install. Textures write into just fine, the folders are made for meshes but nothing is generated. OS shouldn't be interfering as the program is run as administrator, and antivirus is nonexistent on my system:
[00:00] [WastelandNV] Generating Object LOD
[00:15] [WastelandNV] No options file found: Z:\run\media\matthew\Storage\Modding Tools\xLODGEN\Edit Scripts\FNVLODGen_FalloutNV_WastelandNV_Options.txt
[00:15] [WastelandNV] Saving LODGen data: Z:\run\media\matthew\Storage\Modding Tools\xLODGEN\Edit Scripts\LODGen.txt
[00:16] [WastelandNV] Building LOD textures atlas: C:\xLODGen Output Object\textures\landscape\lod\WastelandNV\Blocks\WastelandNV.Buildings.dds with 445 textures
[00:16] <Note: textures\mojave\lod\adobelod_d_n.dds normal map not found, using flat replacement>
[00:20] ============================================================
[00:20] Skyrim/Fallout Object/Terrain LOD Generator 3.0.11.0
[00:20] Created by Ehamloptiran and Zilav
[00:20] Updated by Sheson
[00:20] Log started at 2:52:41 AM
[00:20] .NET Version: 4.8
[00:20] Unhandled Exception: System.IO.IOException: Invalid access.
[00:20] at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
[00:20] at System.Console.set_Title(String value)
[00:20] at LODGeneratorCMD.Program.Main(String[] args) in C:\project\LODGen\LODGeneratorCMD\Program.cs:line 848
[00:20] [WastelandNV] Objects LOD generation error: LODGen process error, exit code E0434352
[00:20] LOD generation complete
FNVLODGen_log.txt