I am using the incoming mail feature of SharePoint 2007 to catch mail from the drop folder and add it to a configured list. We have multiple systems that send automated reports to SharePoint every night, and for some reason it only handles some of the attachments.
For example, an automated email was sent to a SharePoint list with 23 attachments (before you ask, the total size of the combined attachments was less than 1 MB and I have removed all size restrictions from Exchange 2007). Out of the 23 reports, only about 5 were turned into a document item in the list.
The results of this are sporadic and unpredictable, but it always works for some of the attachments and usually not all of the attachments. The lists are configured not to overwrite existing copies of the reports, and I have noticed that SharePoint renames the files by placing a 4 digit number at the end of the name (since each day produces the same report titles).
I have been looking through logs for days and can't seem to come up with an explanation.
Update - I found the following in the Event Logs:
An error occurred while attempting to create an attachment for an item sent via e-mail. The e-mail was sent to the list "Reports", and the error was: Object reference not set to an instance of an object..