Enterprise Managers are no longer starting

Products

• CA Application Performance Management (APM / Wily / Introscope)

Issue/Introduction

After the upgrade of EMs, the MOM Enterprise Manager and collector Enterprise Manager are not starting. The IntroscopeEnterpriseManager.log is showing following error. 

[DEBUG] [main] [Manager] Error starting up EM
com.wily.introscope.server.enterprise.EnterpriseManagerCannotStartException: An error occurred while trying to start Isengard.
 at com.wily.introscope.server.enterprise.EnterpriseServer.doStart(EnterpriseServer.java:421)
 at com.wily.util.ALifeCycle.start(ALifeCycle.java:86)
 at com.wily.introscope.server.enterprise.EnterpriseServer.<init>(EnterpriseServer.java:327)
 at com.wily.introscope.server.enterprise.EnterpriseServer.<init>(EnterpriseServer.java:306)
 at com.wily.introscope.server.enterprise.EnterpriseServer.start(EnterpriseServer.java:1606)
 at com.wily.introscope.em.internal.Activator.startEM(Activator.java:119)
 at com.wily.introscope.em.internal.Application.start(Application.java:27)
 at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:193)
 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:386)
 at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
 at java.lang.reflect.Method.invoke(Method.java:498)
 at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:549)
 at org.eclipse.equinox.launcher.Main.basicRun(Main.java:504)
 at org.eclipse.equinox.launcher.Main.run(Main.java:1236)
 at org.eclipse.equinox.launcher.Main.main(Main.java:1212)
 at org.eclipse.core.launcher.Main.main(Main.java:30)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
 at java.lang.reflect.Method.invoke(Method.java:498)
 at com.zerog.lax.LAX.launch(Unknown Source)
 at com.zerog.lax.LAX.main(Unknown Source)
Caused by: com.wily.isengard.container.BeanActivationException: Error activating bean: com.wily.apm.em.monitor.isengard.support.EventMonitorService (com.wily.apm.em.monitor.isengard.support.EventMonitorService)
 at com.wily.isengard.container.BeanActivator.activateBean(BeanActivator.java:390)
 at com.wily.isengard.container.BeanContainerCore.addBean(BeanContainerCore.java:150)
 at com.wily.isengard.catalog.server.CatalogCore.addBeanToCatalogAndCore(CatalogCore.java:82)
 at com.wily.isengard.catalog.server.CatalogCore.addBean(CatalogCore.java:148)
 at com.wily.isengard.catalog.server.CatalogBean.addBean(CatalogBean.java:66)
 at com.wily.introscope.server.enterprise.EnterpriseServer$ExtensionBeanDescriptor.deploy(EnterpriseServer.java:2680)
 at com.wily.introscope.server.enterprise.EnterpriseServer.startBeans(EnterpriseServer.java:921)
 at com.wily.introscope.server.enterprise.EnterpriseServer.loadBeanExtensions(EnterpriseServer.java:893)
 at com.wily.introscope.server.enterprise.EnterpriseServer.initialize(EnterpriseServer.java:733)
 at com.wily.introscope.server.enterprise.EnterpriseServer.doStart(EnterpriseServer.java:384)
 ... 26 more
Caused by: com.wily.isengard.messageprimitives.InvalidIsengardInterface: The class interface com.wily.apm.em.monitor.isengard.IEventMonitorService must implement interface com.wily.isengard.messageprimitives.service.IMessageService
 at com.wily.isengard.messageprimitives.InterfaceValidationUtilities.validateInterface(InterfaceValidationUtilities.java:20)
 at com.wily.isengard.messageprimitives.service.MessageService.initialize(MessageService.java:82)
 at com.wily.isengard.messageprimitives.service.RegisteredMessageService.registerService(RegisteredMessageService.java:140)
 at com.wily.isengard.messageprimitives.service.RegisteredMessageService.registerService(RegisteredMessageService.java:98)
 at com.wily.isengard.messageprimitives.service.RegisteredMessageService.registerMessageService(RegisteredMessageService.java:128)
 at com.wily.isengard.container.BeanActivator.createMessageService(BeanActivator.java:244)
 at com.wily.isengard.container.BeanActivator.activateBean(BeanActivator.java:371)
 ... 35 more

Environment

Release : 10.7.0 

Component : Introscope

Resolution

It seems like there are some type of corruption exist in product directory. 
We see some files from APM release 10.5, which should not exist there.
Installed a fresh EM collector on another server and once EM is able to run successfully.
We copy /opt/Introscope/APM/product from new EM to collector EM.
We copy /opt/Introscope/APM/product/enterprisemanager from new EM to MOM EM
clear product cache and EMs are able to start on collector and MOM.