STS Fails with "org.eclipse.ui.PartInitException: The file does not exist."

[LinuxLars]

All of a sudden, after working just fine since installation. STS 2.9.2.RELEASE fails to load with:

"Could not open the editor: org.eclipse.ui.PartInitException: The file does not exist."

I've seen threads on Google that indicate it's a missing file in /.metadata/ but deleting /YOUR PATH TO WORKSPACE/.metadata/.plugins/org.eclipse.core.resources doesn't correct the issue.
http://bugsanddebugs.blogspot.com/20...-occurred.html

Here's what's relevant in ../.metadata/.log:

!ENTRY org.eclipse.ui 2 2 2012-06-21 13:12:21.392
!MESSAGE Ignored attempt to add saveable that was already registered
!STACK 0
org.eclipse.core.runtime.AssertionFailedException: unknown saveable: org.eclipse.ui.internal.DefaultSaveable@17d2482 from part: org.eclipse.ui.internal.ErrorEditorPart@17d2482
	at org.eclipse.ui.internal.SaveablesList.logWarning(SaveablesList.java:187)
	at org.eclipse.ui.internal.SaveablesList.addModel(SaveablesList.java:117)
	at org.eclipse.ui.internal.SaveablesList.addModels(SaveablesList.java:289)
	at org.eclipse.ui.internal.SaveablesList.postOpen(SaveablesList.java:695)
	at org.eclipse.ui.internal.PartList.partOpened(PartList.java:234)
	at org.eclipse.ui.internal.PartList.access$0(PartList.java:210)
	at org.eclipse.ui.internal.PartList$1.propertyChanged(PartList.java:40)
	at org.eclipse.ui.internal.WorkbenchPartReference.fireInternalPropertyChange(WorkbenchPartReference.java:375)
	at org.eclipse.ui.internal.WorkbenchPartReference.getPart(WorkbenchPartReference.java:610)
	at org.eclipse.ui.internal.EditorAreaHelper.setVisibleEditor(EditorAreaHelper.java:271)
	at org.eclipse.ui.internal.EditorManager.setVisibleEditor(EditorManager.java:1459)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
        .....

Anyone have any idea how to recover without creating a new workspace?

Thanks

[LinuxLars]

Just an FYI for anyone who comes after. I couldn't find an answer that worked, so I renamed the workspace folder, created a new one, and imported my existing projects into the new folder.

[Andrew Eisenberg]

Try restarting STS with the -clean option. This may work.