Troubleshooting AEM

You are reading the AEM 6.2 version of Troubleshooting AEM.
This documentation is also available for the following versions:  AEM 6.3  AEM 6.1  AEM 6.0  AEM 5.6.1  AEM 5.6  CQ 5.5  CQ 5.4 

The following section covers some issues that you may encounter when using AEM, together with suggestions on how to troubleshoot them.


If you are troubleshooting authoring issues in AEM, see Troubleshooting for Authors.


When experiencing problems it is also worthwhile checking the list of Known Issues for your instance (release and service packs).

Troubleshooting scenarios for Administrators

The following table provides an overview of problems administrators may need to troubleshoot:

Role(s) Problem 
System Administrator

Double-clicking the Quickstart jar does not have any effect or opens the jar file with another program (for example, archive manager)

System Administrator

My application running on CRX throws out-of-memory errors

System Administrator

The AEM Welcome screen does not display in the browser after double-clicking AEM CM Quickstart

System Administrator

admin user

Making a Thread Dump

System Administrator

admin user

Checking for unclosed JCR sessions

Installation Issues

See Common Installation Issues for information about the following troubleshooting scenarios:

  • Double-clicking the Quickstart jar has no effect or the JAR file with another program (such as archive manager).
  • Applications running on CRX throw out-of-memory errors.
  • The AEM Welcome screen does not display in the browser after double-clicking AEM Quickstart.

Methods for Troubleshooting Analysis

Making a Thread Dump

The thread dump is a list of all the Java threads that are currently active. If AEM does not respond properly, the thread dump can help you identify deadlocks or other problems.

Using Sling Thread Dumper

  1. Open the AEM Web Console; for example at http://localhost:4502/system/console/.
  2. Select the Threads under Status tab.

Using jstack (command line)

  1. Find the PID (process id) of the AEM Java instance.
    For example, you can use ps -ef or jps.
  2. Run:
    jstack <pid>
  3. This will show the thread dump.


You can append the thread dumps to a log file by using the >> output redirection:

jstack <pid> >> /path/to/logfile.log

See the How to take Thread Dumps from a JVM documentation for more information

Checking for unclosed JCR sessions

When functionality is developed for AEM WCM, JCR Sessions may be opened (comparable to opening a database connection). If the opened sessions are never closed, your system may experience following symptoms:

  • The system becomes slower.
  • You can see a lot of CacheManager: resizeAll entries in the log file; the following number (size=<x>) shows the number of caches, each sessions opens several caches.
  • From time to time the system runs out of memory (after a few hours, days, or weeks - depending on the severity).

To analyze unclosed sessions and find out which code is not closing a session, refer to the Knowledge Base article Analyze Unclosed Sessions.

Using the Adobe Experience Manager Web Console

The status of the OSGi bundles can also give an early indication of possible issues.

  1. Open the AEM Web Console; for example at http://localhost:4502/system/console/.
  2. Select Bundles under OSGI tab.
  3. Check:
    • the Status of the bundles. If any are Inactive or Unsatisfied, then try to stop and restart the bundle. If the issue persists then you may need to investigate further using other methods.
    • whether any of the bundles have missing dependencies. Such details can be seen by clicking on the individual bundle Name, which is a link (the following example does not have any issues):

Any questions?

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Learn more about AEM topics on our help hub.
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