Be careful when you do this. It removed the Atelier perspective and views for me. I think the errors happened for me in first place because my java setup was messed up somehow. To fix it, I re-installed java and added the vm to the Eclipse shortcut, following suggestion from InterSystems support.  See Target shortcut value below. Keep in mind that your java files might be in a different folder.

"C:\Program Files (x86)\eclipse\eclipse.exe" "-vm C:\Program Files (x86)\Java\jre1.8.0_261\bin\javaw.exe"