My myeclipse also often starts with an error, probably 20% probability. My method is to log out of windows and log in again, 80% can be done. Or restart the computer, the success rate is also 80%
Did you install some other plugins? Try to remove them first, it is probably a problem of version conflict
For how to install plugins, please see the clean plugin installation method in my blog.
org.objectweb.lomboz-all-in-one-R-3.2-201610201336-win32.zip
I used 1.6 for GUI design, but lomboz does not support tomcat6, so I dropped it to 1.5
But it was good before, why not now? Just fine on other computers