When I went to open Eclipse, it had worked an hour before, it froze at launch and gave the error: "An error has occurred. See the log file". See the log file below.
Although some of this information appears in the log,
OS: Mac OSX 10.7.5
Eclipse: Eclipse IDE for C/C++ Developers 3.8
Additionally, I have tried launching the Eclipse executable with -clean, as well as deleting various files in the .metadata folder. Lots of solutions on the internet, none have worked so far.
!SESSION 2012-11-10 22:10:32.651 -----------------------------------------------
eclipse.buildId=M20120914-1800
java.version=1.7.0_09
java.vendor=Oracle Corporation
BootLoader constants: OS=macosx, ARCH=x86_64, WS=cocoa, NL=en_US
Framework arguments: -product org.eclipse.epp.package.cpp.product -keyring /Users/Puzzel/.eclipse_keyring -showlocation
Command-line arguments: -os macosx -ws cocoa -arch x86_64 -product org.eclipse.epp.package.cpp.product -keyring /Users/Puzzel/.eclipse_keyring -showlocation
!ENTRY org.eclipse.core.net 1 0 2012-11-10 22:10:35.937
!MESSAGE System property http.nonProxyHosts has been set to local|*.local|169.254/16|*.169.254/16 by an external source. This value will be overwritten using the values from the preferences
!ENTRY org.eclipse.osgi 4 0 2012-11-10 22:10:36.479
!MESSAGE Application error
!STACK 1
org.eclipse.swt.SWTException: Failed to execute runnable (java.lang.NullPointerException)
at org.eclipse.swt.SWT.error(SWT.java:4361)
at org.eclipse.swt.SWT.error(SWT.java:4276)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:138)
at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:3944)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3621)
at org.eclipse.swt.widgets.Display.release(Display.java:3682)
at org.eclipse.swt.graphics.Device.dispose(Device.java:190)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:140)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:353)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:180)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:629)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:584)
at org.eclipse.equinox.launcher.Main.run(Main.java:1438)
Caused by: java.lang.NullPointerException
at org.eclipse.ui.internal.Workbench.createWorkbenchWindow(Workbench.java:1231)
at org.eclipse.ui.internal.Workbench.getActiveWorkbenchWindow(Workbench.java:1224)
at org.eclipse.cdt.codan.internal.ui.cxx.Startup$1.run(Startup.java:39)
at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:135)
... 17 more
!ENTRY org.eclipse.mylyn.monitor.ui 4 0 2012-11-10 22:10:36.569
!MESSAGE Monitor UI stop failed
!STACK 0
java.lang.NullPointerException
at org.eclipse.mylyn.internal.monitor.ui.ActivityContextManager.stop(ActivityContextManager.java:152)
at org.eclipse.mylyn.internal.monitor.ui.MonitorUiPlugin.stop(MonitorUiPlugin.java:157)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl$2.run(BundleContextImpl.java:771)
at java.security.AccessController.doPrivileged(Native Method)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.stop(BundleContextImpl.java:764)
at org.eclipse.osgi.framework.internal.core.BundleHost.stopWorker(BundleHost.java:510)
at org.eclipse.osgi.framework.internal.core.AbstractBundle.suspend(AbstractBundle.java:566)
at org.eclipse.osgi.framework.internal.core.Framework.suspendBundle(Framework.java:1206)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.decFWSL(StartLevelManager.java:592)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.doSetStartLevel(StartLevelManager.java:257)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.shutdown(StartLevelManager.java:215)
at org.eclipse.osgi.framework.internal.core.InternalSystemBundle.suspend(InternalSystemBundle.java:284)
at org.eclipse.osgi.framework.internal.core.Framework.shutdown(Framework.java:692)
at org.eclipse.osgi.framework.internal.core.Framework.close(Framework.java:600)
at org.eclipse.core.runtime.adaptor.EclipseStarter.shutdown(EclipseStarter.java:399)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:199)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:629)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:584)
at org.eclipse.equinox.launcher.Main.run(Main.java:1438)
!ENTRY org.eclipse.core.jobs 2 2 2012-11-10 22:10:36.917
!MESSAGE Job found still running after platform shutdown. Jobs should be canceled by the plugin that scheduled them during shutdown: org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin$TasksUiInitializationJob
!ENTRY org.eclipse.core.jobs 2 2 2012-11-10 22:10:36.918
!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
Deleting workspace/.metadata/.plugins/org.eclipse.e4.workbench/workbench.xmi
solved the problem.
See this answer.