Since our ECC 6.0 upgrade we have been facing a problem related to GuiXT. One of our transactions YGUIXTMM is not working properly. Only the Menu bar appears and nothing else works. Can you please help?

I suggest you install the latest GuiXT version on one of the PCs; earlier GuiXT versions are not compatible with ECC 6.0. Please click on "Help"- >"About" in the GuiXT window after the installation to verify that the correct GuiXT version is active.