Figure 1
 

Delete e-mail messages from sync issues folder within Outlook using the following steps:

1. View by Folder List.
2. Expand Sync Issues.
3. Highlight Server Failures or appropriate folder referenced in the error message.
4. Delete all files within the folder.
5. Retry the backup job.

Additional information from Microsoft Article 870926 (http://support.microsoft.com/kb/870926)

Outlook 2003 Sync Issues folder
Outlook 2003 will skip and log any bad items or malformed items on the server, and then Outlook 2003 continues to synchronize correctly. Bad items are put in the appropriate Server Failures folder or in the appropriate Local Failures folder in the Sync Issues folder. The Sync Issues folder and its sibling folders are visible only in the Folder List view of the Navigation pane. They do not appear in the All Mail Folders list in the Mail section of the Navigation pane.