ESM and Journaling not processing messages Error: "[80040154] Class not registered" in MailboxID-xx-yyyymmdd.log and DataLoaderID-x-yyyymmdd.log (4268774)

You notice that Journaling and ESM are not processing any messages. After looking at the MailboxID-xx-yyyymmdd.log and DataLoaderID-x-yyyymmdd.log you notice the following error:

14:27:53 ERROR: MIMEHeaderParser.CreateInstance:

14:27:53  [80040154] Class not registered

You will also see similar errors in the Mailbox Scan Status page. 

1. Stop the Exchange Store Manager and Dataloader service.

2. Open the command prompt window as Administrator

3. Change to the AM install directory. "C:\Program Files (x86)\Dell\Archive Manager" or "C:\Program Files (x86)\Quest\Archive Manager"

4. Run the following command:

If running 5.3:

C:\Windows\Microsoft.NET\Framework\v4.0.30319\regasm.exe Dell.AM.ESM.Mlib.dll

If running 5.4:

C:\Windows\Microsoft.NET\Framework\v4.0.30319\regasm.exe Quest.AM.ESM.Mlib.dll

5. Start the Exchange Store Manager and Dataloader service.

6. Monitor the logs files to determine if messages are now being processed.