Long pauses when debugging, NoClassDefFoundError for XmlPullParserException in console

I've recently been getting long beachball pauses in the IDE while debugging. When I look at idea.log, I always see the error below at the same time. Any idea what's causing this or how I can fix it?



2014-10-01 11:21:17,386 [608504050]  ERROR - .impl.MessageBusConnectionImpl - org/xmlpull/v1/XmlPullParserException
java.lang.NoClassDefFoundError: org/xmlpull/v1/XmlPullParserException
 at org.xmlpull.v1.XmlPullParserFactory.newInstance(XmlPullParserFactory.java:294)
 at org.xmlpull.v1.XmlPullParserFactory.newInstance(XmlPullParserFactory.java:259)
 at com.intellij.execution.console.ConsoleHistoryController$ModelHelper.saveHistory(ConsoleHistoryController.java:417)
 at com.intellij.execution.console.ConsoleHistoryController$ModelHelper.access$200(ConsoleHistoryController.java:350)
 at com.intellij.execution.console.ConsoleHistoryController.saveHistory(ConsoleHistoryController.java:161)
 at com.intellij.execution.console.ConsoleHistoryController.access$100(ConsoleHistoryController.java:66)
 at com.intellij.execution.console.ConsoleHistoryController$1.saved(ConsoleHistoryController.java:103)
 at sun.reflect.GeneratedMethodAccessor154.invoke(Unknown Source)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 at java.lang.reflect.Method.invoke(Method.java:597)
 at com.intellij.util.messages.impl.MessageBusConnectionImpl.deliverMessage(MessageBusConnectionImpl.java:114)
 at com.intellij.util.messages.impl.MessageBusImpl.doPumpMessages(MessageBusImpl.java:228)
 at com.intellij.util.messages.impl.MessageBusImpl.pumpMessages(MessageBusImpl.java:219)
 at com.intellij.util.messages.impl.MessageBusImpl.sendMessage(MessageBusImpl.java:209)
 at com.intellij.util.messages.impl.MessageBusImpl.access$000(MessageBusImpl.java:43)
 at com.intellij.util.messages.impl.MessageBusImpl$1.invoke(MessageBusImpl.java:131)
 at com.sun.proxy.$Proxy98.saved(Unknown Source)
 at com.intellij.openapi.project.impl.ProjectImpl.save(ProjectImpl.java:376)
 at com.intellij.openapi.project.impl.ProjectManagerImpl.writeExternal(ProjectManagerImpl.java:1125)
 at com.intellij.openapi.components.impl.stores.DefaultStateSerializer.serializeState(DefaultStateSerializer.java:51)
 at com.intellij.openapi.components.impl.stores.XmlElementStorage$MyExternalizationSession.setState(XmlElementStorage.java:272)
 at com.intellij.openapi.components.impl.stores.StateStorageManagerImpl$MyExternalizationSession.setStateInOldStorage(StateStorageManagerImpl.java:419)
 at com.intellij.openapi.components.impl.stores.ComponentStoreImpl$SaveSessionImpl.commit(ComponentStoreImpl.java:451)
 at com.intellij.openapi.components.impl.stores.ComponentStoreImpl.startSave(ComponentStoreImpl.java:105)
 at com.intellij.openapi.components.impl.stores.StoreUtil.doSave(StoreUtil.java:30)
 at com.intellij.openapi.application.impl.ApplicationImpl._saveSettings(ApplicationImpl.java:1388)
 at com.intellij.openapi.application.impl.ApplicationImpl.saveSettings(ApplicationImpl.java:1427)
 at com.intellij.ide.SaveAndSyncHandlerImpl.saveProjectsAndDocuments(SaveAndSyncHandlerImpl.java:154)
 at com.intellij.ide.SaveAndSyncHandlerImpl$3.onFrameDeactivated(SaveAndSyncHandlerImpl.java:103)
 at com.intellij.ide.FrameStateManagerImpl.fireDeactivationEvent(FrameStateManagerImpl.java:87)
 at com.intellij.ide.FrameStateManagerImpl.access$500(FrameStateManagerImpl.java:32)
 at com.intellij.ide.FrameStateManagerImpl$2$1.run(FrameStateManagerImpl.java:72)
 at com.intellij.util.concurrency.QueueProcessor.runSafely(QueueProcessor.java:238)
 at com.intellij.util.Alarm$Request$1.run(Alarm.java:327)
 at com.intellij.openapi.application.impl.LaterInvocator$FlushQueue.run(LaterInvocator.java:318)
 at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
 at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:715)
 at java.awt.EventQueue.access$400(EventQueue.java:82)
 at java.awt.EventQueue$2.run(EventQueue.java:676)
 at java.awt.EventQueue$2.run(EventQueue.java:674)
 at java.security.AccessController.doPrivileged(Native Method)
 at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:86)
 at java.awt.EventQueue.dispatchEvent(EventQueue.java:685)
 at com.intellij.ide.IdeEventQueue.defaultDispatchEvent(IdeEventQueue.java:722)
 at com.intellij.ide.IdeEventQueue._dispatchEvent(IdeEventQueue.java:549)
 at com.intellij.ide.IdeEventQueue.dispatchEvent(IdeEventQueue.java:360)
 at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:296)
 at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:211)
 at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:201)
 at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:196)
 at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:188)
 at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)