when i run a hello world it come up with "edit invalid project settings" and i don't know what to do as when i click on a toolchain EG GNU tools for STM32, it still says what do i do?

I would just follow promoted process. Let's click on "Open Toolchain Manager" button ... as reported trouble is "unkown toolchain".

Most probably your current project is relying on a toolchain which not available (have you updated IDE ?) .... toolchain manager will help you to install it. Or move to project settings assigning it to currently installed one if you're not fixed on a specific toolchain version.

Is this after CubeIDE update to version 1.6?

If so, try to "repair" the previous ARM toolchain which the debugger was using previously.

• Open  Toolchain Manager (it will take its time .... patience....) then select "Add Local".
• Then browse to the toolchain before update to 1.6.0 , usually it is "7-2018". Go to the bin subdirectory under it and select that.
• Give it any name, for example "Old toolchain".

Then it will be available in Toolchain manager and you can select it for the debugger. The the debugger should work.

-- pa

First: why do you add a local toolchain ? sounds the one you'trying to install as local is already part of installed toolchain according toolchain manager status

Second: if aiming anyway to point by yourself to a local toolchain I guess "features" path is not ok ... let's try "plugins" instead ... you have to provide path to repository where toolchain binaries are

My advice is still to rely on first :) ... then look at project properties to point to expected toolchain: