There are several reasons for items to be missing, or to appear to be missing.

1. Check to see if the migration completed successfully and without any errors. If there were errors, consider performing a repair migration pass to allow missing items to migrate.
2. Check to see if the missing items are special items that we do not migrate. The list of ite​​ms we do not migrate can be found here.
3. Check to see if the missing items are stored on the Source server (i.e., not in a local PST file). If possible, use a web client to verify the content of the Source mailbox.
4. Check to see if the missing items are stored on the Destination server. Some clients may need to "subscribe" to folders for them to appear, or may take time to download items. If possible, use a web client to verify the content of the Destination mailbox.
5. Check to see if the missing items were not moved to a new location on the Destination server (i.e., Outlook automatically archived old content after the migration). If possible, do a search across all folders.
6. Check to see if your mailbox connector or mailbox has any advanced filtering option specified. For example, a date filter, a folder filter, or an object type filter may result in a partial migration.
7. Check to see if the Source items have any type of special permissions set on them. In some rare cases, the folder can be read but cannot migrate some items.
8. Check to see if any folder was renamed, or items moved between folders while the migration was in progress. This may, in some rare cases, cause items to be missing.
9. Check to see if the Destination system did not move migrated items to the Junk mail folder because of anti-spam processing. Some Destination email systems will apply anti-spam to migrated items.
10. Check to see if missing items were received by the Source while the migration was in progress. We recommend performing a multi-pass migration to migrate residuals after the migration completes.
11. Check to see if missing items are readable at the Source. Some archive systems such as Symantec Enterprise Vault may cause only stub items to be returned by access APIs.

Note: MigrationWiz remembers which items have been migrated. If you deleted items at the Destination after migration, and then resubmit a migration, we will NOT remigrate the items you deleted at the Destination. You will need to reset the statistics of your migration first, then resubmit.

The BitTitan Audit Logging Service allows you to compare items between the Source and Destination to analyze the difference. However, verifying the above points will expedite our investigation. In most cases, we will require screen shots demonstrating that an item is missing to facilitate investigation.