We recently saw more and more users running into the situation that the installation of the Dynamics AX 2009 Application Object Server is failing.

The log file that is created during the installation showed the following information:

MSI (s) (FC:9C) [18:26:21:017]: Leaked MSIHANDLE (6) of type 790531 for thread 4888 MSI (s) (FC:9C) [18:26:21:017]:
Note:
1: 2769
2: Aos.Install
3: 1 Error 1001.
Microsoft Dynamics AX Setup - Custom Action: AOS Server - Install An error occurred during the install custom action step within the AOS Server installer --> Only the first eight characters of a custom log name are significant, and there is already another log on the system using the first eight characters of the name given.
Name given: 'Microsoft Dynamics AX Workflow', name of existing log: Microsoft-Windows-Forwarding/Op'erational'.
DEBUG: Error 2769: Custom Action Aos.
Install did not close 1 MSIHANDLEs.
Internal Error 2769. Aos.Install, 1

When the Dynamics AX 2009 Application Object Server is installed, it is creating a new Eventlog for the Workflow Service. The Eventlog is named Microsoft Dynamics AX Workflow. The important part is the beginning of the name, as the first eight characters of the name are checked to be unique.

The Windows Installer Custom Action that is creating the Eventlog is however not checking if an Eventlog with matching first eight characters already exists and while attempting to create the new Eventlog the operation fails, which causes the whole Custom Action to fail, which causes Windows Installer to roll back the installation.

In this specific case the existing Eventlog Microsoft-Windows-Forwarding/Operational was created by the Windows Event Collector.

 

The Eventlogs currently existing are registered under following Registry Key (each Eventlog has its own Sub Key):

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Eventlog

 

We were able to install the Dynamics AX 2009 Application Object Server by renaming the existing conflicting Eventlog name (Registry Sub Key) at the above location and renaming the Registry Key back after the AOS was successfully installed.