Hello 
I’ve got a problem. The thing is: in Power Up when you are going to that generator room, and you destroy Gargantua there is a blue cloud (and I used to have it) but now it is gone. I’m not sure if it has something to do with it, but in console there is something like: “Unable to create an unknown particle system gargantua_gib_fx”. Is it problem with my files; or because I installed On a Rail Uncut? Or maybe both? I know that this problem is a Nit-Pick but I like to have everything perfect, you know :3 Is there any way to fix this? Thank You in advance 
Chances are your particle system files disappeared or got replaced.
Here, I reuploaded the folder for you, just place it back into your BMS folder: https://mega.co.nz/#!PgIh2IpL!B8PQCwJDoOremMRBX8hhM17reSZV3CMJpRPJuDsaIzw
Well that almost worked… I loaded mah save and shocked that Gargantua and there was that blue cloud, then just to make sure that it works I loaded save again and this time there wasn’t that effect.
Check your console and tell me if the error comes back again.
Go to your BMS\particles folder, is there 101 pcf files in it?
OK, so, sorry for late reply. I have got all 101 pcf files. And also that error about Unable to create/Attempted to create an unknown particle system is still showing in console.
EDIT: It also says Attempted to precache an unknown particle system gargantua_gib_fx.
It’s most likely the particle_manifest.txt that causes the issue.
Redownload BMS content (the .rar is required), and replace everything and try again.
OK, I will try it, and I will tell you if that worked.
OK, so, I didn’t re-install Black Mesa yet but I have extracted the particle_manifest.txt from .rar archive and I have loaded my save 6 times. One out of six times didn’t have blue cloud, so I guess, it is somewhat fixed… But just in case of emergency, I will post my problems here. But now I want to Thank You, for your help, and your time that you used to help me. Thank You
Always ready to help when I can.