Just got Unity 5.5 and can't use Noesis anymore:
1. I don't see the Noesis main menu entry
2. Editor shows this error:
Assets\Editor\NoesisGUI\Platform_.cs(4,12): error CS1029: #error: 'DirectX is not active! Please, activate it in Tools -> NoesisGUI -> Settings'

However, because of #1, I can't activate it.

Is this a known issue and is there a patch/fix I could apply? Thanks a lot!

1.2.6f5 as downloaded from the sticky here is working correctly for me in 5.5 f2 x64 on Windows, so might be a compiler or platform issue?

Thanks for the reply!
Found a workaround:
1. In Assets\Editor\NoesisGUI\Platform_.cs, remove the error line:
#if UNITY_STANDALONE_WIN
REMOVE THIS LINE: # error DirectX is not active! Please, activate it in Tools -> NoesisGUI -> Settings
#endif

Then Tools | NoesisGUI shows up and can work.

The issue happened because I had the target set to Android and no DX building in Unity 5.4. However in 5.5, the runtime won't build if there are player errors even if for different platform (this is a change in 5.5.) Thus I had to manually edit the auto-generated platform_.cs

This automatic generated script, Platform_.cs, is one thing we don't like in our current Unity integration, and we will change it for sure for the next version.

As you found, the only way to solve the undesired situation you described is by commenting/deleting that script, so Unity would be able to compile the Editor assembly and NoesisGUI menu can be shown again.

Sorry for the inconvenience.

No problem, I'm glad it worked!