Plugin processing: The plugin will be disabled because it crashed QGIS during last startup. Please report an issue and re-enable the plugin when the problem has been solved. I have this problem in my QGIS , how do I can solve it?
Do you still have the processing plugin under C:\users\username.qgis2\python\plugins? If yes, delete it and try again.
Processing is now a core feature, stored in the programs subfolder.