Eclipse霓虹灯挂起加载org.eclipse.ui.navigator

Question

Researching existing answers to problems with eclipse hanging on startup, I have not found anything that seems applicable to my problem. Neither have the responses so far been helpful.

The splash screen appears and seems to be conducting a normal startup process, but when the status message reports

Loading org.eclipse.ui.navigator

all progress halts, apparently forever.
REACTIONS TO ADVICE AND DIAGNOSTICS:
A related question caused me to add -clean to the shortcut. This did not help.
The first actual answer suggested reinstalling Eclipse. This did not help.
The second response suggested that I look at Eclipse log files. The first file suggested was most recently updated May 5, long before the problems started, and the second suggested file did not exist.
Moving the old workspace to a different file name and reinstalling Eclipse again with a brand-new workspace enabled me to launch Eclipse successfully, but if I switch workspaces to the new workspace, it hangs (at the same point).
The problem appears to be loading a plugin named org.eclipse.ui.navigator . There is no such plugin in {workspace}\\.metadata\\.plugins, in either the old workspace or the new workspace. I don't know why Eclipse is trying to load that nonexistent plugin when it tries to run from the old workspace but not from the new workspace. As far as I can tell I need to find some way to install the navigator plugin in the old workspace (without being able to run Eclipse from that workspace), or somehow tell Eclipse not to try to load it. I have no idea how to do either.
Running Eclipse Neon, on a Win10 machine; Eclipse ran normally as of a few days earlier and only started hanging May 22.

Answer 1

Had the same problem today. It was resolved after removing the following folders from the [workspace]/.metadata/.plugins folder:

org.eclipse.e4.ui.workbench.swt
org.eclipse.e4.workbench