Generally, these local failures occur with recurring appointments that have data in them that Outlook cannot handle. Sometimes this can happen from bad migrations, messages from other clients that support features that Outlook does not, previous bugs, etc. An example would be something like this:
A recurring meeting that recurs every Thursday with an update to a recurrence. The update refers to a recurrence on a Wednesday.
Outlook cannot process this, so we give a local failure. We don't want to sync this to Outlook, because if you then modify things, you'll get even more out of sync. We used to sync it, and we found there were more problems.
These errors always go in the Sync Issues -> Local Failures folder (this is an Outlook thing). However, customers complained that they weren't seeing these errors, so we also put them in the Inbox. In 5.0.12, I added some UI so you don't need to use the registry key if you dont' want to see them in the Inbox. Just do View->Errors to Inbox, and uncheck it.
Note that local failures can happen for other reasons as well -- like being unable to download HTML, etc. There are also Server errors and Conflict errors.
As far as debugging the error, you can post that log file, or what's better would be just to post those xml files that came with the local failure, as well as the complete text of the local failure message. I can take a look and probably identify why you are getting the failure.  |