I might be silly but when i move to lts 2026 my console says it can't find the runtime and to update it with --runtime in the console. However I'm not sure what that means, i blindly tried a couple commands that didn't work and I couldn't find any mention of this process on the docs. I also tried reinstalling the library in case that would auto find the right folders but it didn't seem to help.  Being on the old version works fine, new version has this issue. Is there somewhere that explains this or is it just not working? Haven't seen anything else so I assume it's working? 

Either way, thank you.

Ah, this only shows up when using shader_set_live because GMLive needs to use GM’s HLSLCompiler.exe (which is in the runtime directory) but LTS2026 added another folder in ProgramData that GMLive-server doesn’t know about.

You’ll want to open the directory where gmlive-server is, open Command Prompt or PowerShell (shift-right-click on an empty spot) and do something like this

.\gmlive-server.exe --runtimePath C:\ProgramData\GameMakerStudio2-LTS2026\Cache\runtimes\runtime-2026.0.0.23

(replace the version number with your own if necessary)

Edit: 1.0.79’s server is now aware of LTS2026 runtimes folder.

Aha, that did indeed fix it. Awesome, and perhaps other people will find this useful when they search here. Guess they're not using shader replace heh.