This is because of upgrade is not done properly. During the upgrade few packages is not upgraded from older version to new version due to javax.jcr.nodetype.ConstraintViolationException. This is because of custom code has updated 'rep:externalId' to the users and system user in the AEM 6.2 instance....

I am upgrading from AEM 6.2 [6.2.0.SP1] to AEM 6.4. Do i need to install CFP package before upgrade. Post upgrade SP5 installation also didn't fix the problem.

Post upgrade from AEM 6.2 with SP2 to AEM 6.4 few of the packages are in not installed. The older version is on installed state.For the new package is showing the message as "A different version seems to be installed:"When i am trying to install manually i am getting the error javax.jcr.nodetype.Con...

I have added all the pom dependency with Junit, WCM io, Sling Jcr dependency.But still when i am running junit the below error is throwing when resource is adopting to page or node.java.lang.NoSuchMethodError: org.osgi.framework.BundleContext.getServiceReference(Ljava/lang/Class;)Lorg/osgi/framework...

Is there any example for customizing sites action bar in touch UI?Like copy the page in sites actionbar need to add custom button in sites actionbar.

After upgrade also you can add workflow service user to Super user list in the Granite workflow configuration. This could be AEM 6.1 is using workflow session is admin session  but in AEM 6.3 workflow session is created from workflow service user which is introduced newly.

Thanks Jorg, kautuksahni for your answer. After using -Doak.documentMK.disableLeaseCheck=true upgrade is completed. Not able to see java.lang.OutOfMemoryError exception. But still workflow migration step got failed due to the below error.Is this below error also insufficient heap memory problem?   *...

I am trying to upgrade AEM 6.1 to AEM 6.3 cluster instance. The in place upgrade is failed due to below error.15.11.2017 11:50:36.704 *ERROR* [DocumentNodeStore background update thread (8)] org.apache.jackrabbit.oak.plugins.document.ClusterNodeInfo This oak instance failed to update the lease in ti...

We found that few ACL's which is applied in libs path causing this issue. We are analyzing further how ACL's are affected after upgrade. 

I am doing upgrade from AEM 6.1 author with mongodb to AEM 6.3 author.     Step 1: pre upgrade task is done     Step 2: Replaced AEM 6.1 jar with AEM 6.3 jar alone parallel AEM 6.1 crx instance     Step 3: Unpacked AEM 6.3 jar with runmode mongo and it shows                  - Build number changed, ...