Eclipse won't start after changing workspace

Question

I've screwed up my Eclipse installation. I changed the workspace location (File->Switch Workspace). Now it won't startup. I see the splash for a few seconds and it shuts down. I then tried using the -data parameter on the command line with both the old and the new workspace, but same behavior. I also tried rebooting the machine.

In eclipse\workspace.metadata.plugins\org.eclipse.core.runtime.settings\org.eclipse.ui.ide.prefs, I added the last line for SHOW_WORKSPACE_SELECTION_DIALOG, but no difference.

EXIT_PROMPT_ON_CLOSE_LAST_WINDOW=false
IMPORT_FILES_AND_FOLDERS_RELATIVE=true
IMPORT_FILES_AND_FOLDERS_TYPE=23,1
PROBLEMS_FILTERS_MIGRATE=true
SWITCH_PERSPECTIVE_ON_PROJECT_CREATION=always
TASKS_FILTERS_MIGRATE=true
eclipse.preferences.version=1
platformState=1346849854920
quickStart=false
tipsAndTricks=true
SHOW_WORKSPACE_SELECTION_DIALOG=true

How do I get it back?

(Edit) I removed the .metadata directory and then Eclipse restarted.

Snip from log file:

!SESSION 2013-01-28 10:35:51.245 -----------------------------------------------
eclipse.buildId=M20120914-1800
java.version=1.7.0_07
java.vendor=Oracle Corporation
BootLoader constants: OS=win32, ARCH=x86_64, WS=win32, NL=en_US
Framework arguments:  -product org.eclipse.epp.package.java.product
Command-line arguments:  -os win32 -ws win32 -arch x86_64 -product org.eclipse.epp.package.java.product

!ENTRY org.eclipse.ui 4 4 2013-01-28 10:32:40.278
!MESSAGE Unhandled Exception

!ENTRY org.eclipse.ui 4 0 2013-01-28 10:32:40.278
!MESSAGE Error occurred during status handling
!STACK 0
java.lang.NullPointerException
    at org.eclipse.ui.internal.statushandlers.StatusHandlerRegistry.<init>(StatusHandlerRegistry.java:72)
...
!ENTRY org.eclipse.equinox.p2.ui.sdk.scheduler 4 0 2013-01-28 10:32:40.294
!MESSAGE Unable to execute early startup code for an extension
!STACK 1
org.eclipse.core.runtime.CoreException: Plug-in "org.eclipse.equinox.p2.ui.sdk.scheduler" was unable to instantiate class "org.eclipse.equinox.internal.p2.ui.sdk.scheduler.AutomaticUpdateScheduler".
    at org.eclipse.core.internal.registry.osgi.RegistryStrategyOSGI.throwException(RegistryStrategyOSGI.java:194)
...
!SUBENTRY 1 org.eclipse.equinox.registry 4 1 2013-01-28 10:32:40.294
!MESSAGE Plug-in "org.eclipse.equinox.p2.ui.sdk.scheduler" was unable to instantiate class "org.eclipse.equinox.internal.p2.ui.sdk.scheduler.AutomaticUpdateScheduler".
!STACK 0
java.lang.NullPointerException
    at org.eclipse.equinox.internal.p2.ui.sdk.scheduler.AutomaticUpdateScheduler.<init>(AutomaticUpdateScheduler.java:68)
...
!ENTRY org.eclipse.equinox.p2.ui.sdk.scheduler 4 0 2013-01-28 10:32:40.294
!MESSAGE Unable to execute early startup code for an extension
!STACK 1
org.eclipse.core.runtime.CoreException: Plug-in "org.eclipse.equinox.p2.ui.sdk.scheduler" was unable to instantiate class "org.eclipse.equinox.internal.p2.ui.sdk.scheduler.AutomaticUpdateScheduler".
    at org.eclipse.core.internal.registry.osgi.RegistryStrategyOSGI.throwException(RegistryStrategyOSGI.java:194)
...
!SUBENTRY 1 org.eclipse.equinox.registry 4 1 2013-01-28 10:32:40.294
!MESSAGE Plug-in "org.eclipse.equinox.p2.ui.sdk.scheduler" was unable to instantiate class "org.eclipse.equinox.internal.p2.ui.sdk.scheduler.AutomaticUpdateScheduler".
!STACK 0
java.lang.NullPointerException
    at org.eclipse.equinox.internal.p2.ui.sdk.scheduler.AutomaticUpdateScheduler.<init>(AutomaticUpdateScheduler.java:68)
...
!ENTRY org.eclipse.ui 4 0 2013-01-28 10:32:40.294
!MESSAGE Error occurred during status handling
!STACK 0
java.lang.NullPointerException
    at org.eclipse.ui.internal.statushandlers.StatusHandlerRegistry.<init>(StatusHandlerRegistry.java:72)
...
!ENTRY org.eclipse.core.jobs 2 2 2013-01-28 10:32:40.809
!MESSAGE Job found still running after platform shutdown.  Jobs should be canceled by the plugin that scheduled them during shutdown: org.eclipse.epp.internal.mpc.ui.wizards.MarketplaceDropAdapter$1

!ENTRY org.eclipse.core.jobs 2 2 2013-01-28 10:32:40.809
!MESSAGE Job found still running after platform shutdown.  Jobs should be canceled by the plugin that scheduled them during shutdown: org.eclipse.epp.internal.mpc.ui.wizards.MarketplaceDropAdapter$1

!ENTRY org.eclipse.ui 4 0 2013-01-28 10:32:40.809
!MESSAGE Error occurred during status handling
!STACK 0
java.lang.NullPointerException
    at org.eclipse.ui.internal.statushandlers.StatusHandlerRegistry.<init>(StatusHandlerRegistry.java:61)
...

Answer 1

Find the file org.eclipse.ui.ide.prefs in your

eclipse\configuration\.settings

folder.

Change

SHOW_WORKSPACE_SELECTION_DIALOG=false

to true.