1 Fatal Error

[Its-Robito]

@Lisias I could really use your help with this one, I took a peek at the logs and couldn't find a source but I think it may either have to do with MechJeb or Tweakscale. I've attached the Log, thanks in advance for your time and help!
KSP.log

Edit: it somehow got worse...
KSP.log
(new log after uninstalling, reinstalling and verifying files)

[Lisias]

Hi, @Its-Robito . I'm looking into your issue.

(MechJeb is another one that is very susceptible to that pesky Reflection exceptions...)

[Lisias]

Here, found the problem!

You need to install the following dependencies:

[WRN 22:18:49.075] AssemblyLoader: Assembly 'MechJebRPM' has not met dependency 'MechJeb2' V2.5.0
[WRN 22:18:49.075] AssemblyLoader: Assembly 'MechJebRPM' has not met dependency 'MechJebLib' V0.0.0
[WRN 22:18:49.075] AssemblyLoader: Assembly 'MechJebRPM' is missing 2 dependencies
[WRN 22:18:49.075] AssemblyLoader: Assembly 'SCANmechjeb' has not met dependency 'MechJeb2' V2.5.0
[WRN 22:18:49.075] AssemblyLoader: Assembly 'SCANmechjeb' is missing 1 dependencies
[ERR 22:18:49.130] ADDON BINDER: Cannot resolve assembly: USIToolsUI, Culture=neutral, PublicKeyToken=null

[ERR 22:18:49.131] ADDON BINDER: Cannot resolve assembly: USIToolsUI, Culture=neutral, PublicKeyToken=null

[ERR 22:18:49.146] ADDON BINDER: Cannot resolve assembly: EVEManager, Culture=neutral, PublicKeyToken=null

[ERR 22:18:49.147] ADDON BINDER: Cannot resolve assembly: EVEManager, Culture=neutral, PublicKeyToken=null

[ERR 22:18:49.147] ADDON BINDER: Cannot resolve assembly: Utils, Culture=neutral, PublicKeyToken=null

[ERR 22:18:49.148] ADDON BINDER: Cannot resolve assembly: Utils, Culture=neutral, PublicKeyToken=null

[ERR 22:18:49.205] ADDON BINDER: Cannot resolve assembly: SCANsat.Unity, Culture=neutral, PublicKeyToken=null

[ERR 22:18:49.206] ADDON BINDER: Cannot resolve assembly: SCANsat.Unity, Culture=neutral, PublicKeyToken=null

When you miss a dependency, something inside KSP (a thingy called Assembly Loader/Resolver) and this thingy is the cornerstone of a feature called Reflection, that some more sofisticated add'ons needs to work (like MechJeb, TweakScale, that KSPe stunt of mine...), and from this point everything that the kitchen's sink that needs that Reflection thingy just blows up into space in the more unpleasant way possible.

Anyway, install MechJeb and USIToolsUI and you should be fine.

I will check your second KSP log now.

[Lisias]

Ok, found the second problem. It's not worse than the first one, to tell the truth - it's better, because now you have only ONE problematic issue, and it was detected and pinpointed in the log.

Someone is double patching a part called OctoSat_Con_RCS, and I found it on Octosat:

[LOG 23:59:29.058] Applying update NSS/NSS_MM_TweakScale/@PART[OctoSat_Con*]:NEEDS[TweakScale] to NSS/Parts/OctoSat_Con_RCS.cfg/PART[OctoSat_Con_RCS]
[LOG 23:59:29.058] Applying update NSS/NSS_MM_TweakScale/@PART[OctoSat_Con*]:NEEDS[TweakScale] to NSS/Parts/OctoSat_Con_RCS2.cfg/PART[OctoSat_Con_RCS2]
[LOG 23:59:29.058] Applying update NSS/NSS_MM_TweakScale/@PART[OctoSat_Con*]:NEEDS[TweakScale] to NSS/Parts/OctoSat_Con_RCS3.cfg/PART[OctoSat_Con_RCS3]
[LOG 23:59:29.060] Applying update NSS/NSS_MM_TweakScale/@PART[OctoSat_Con_RCS]:NEEDS[TweakScale] to NSS/Parts/OctoSat_Con_RCS.cfg/PART[OctoSat_Con_RCS] <---- HERE!!!!!

Trivia: I found someone talking about this specific path on Forum.

In a way or another: double patching was found to be involved on some serious misbehaviours on KSP in the past, and it's the reason I'm wide mouthed about. Octosat, sadly, doesn't have a presence on some code management system like github, so I can't apply a pull request with the fix - so I'm publishing a hotfix for you: NSS_MM_TweakScale_fix.cfg.zip .

Shove this file (after unzipping it!) somewhere in your KSP (I strongly suggest GameData/__LOCAL/TweakScale/HotFixes) and then TweakScale will stop yelling at you. At least, about this issue.

Follows the patch for indexing:

// fixes https://github.com/TweakScale/TweakScale/discussions/361

@PART[OctoSat_Con_RCS]:NEEDS[TweakScale]:FINAL
{
	-MODULE[TweakScale],* { }
	
	#@TWEAKSCALEBEHAVIOR[Engine]/MODULE[TweakScale] { }
	%MODULE[TweakScale]
	{
		type = stack
		defaultScale = 1.25
	}
}

[Its-Robito]

Awesome that seemed to do the trick, thank you so much for the help and actually explaining what I'm looking at, really appreciate it