Difference Between Total and Migrated Items
Understanding why item counts may differ after migration.
Overview
After mailbox migration completion, the number of migrated emails may differ from the total items in the source mailbox. This discrepancy doesn't indicate missing emails — it's expected behavior due to how the migration platform processes content.
Item Classification
Non-Mail Items Are Excluded
What Gets Skipped
Items stored in a mail folder that are not classed as mail will not be migrated. Examples include:
- • Calendar invitation objects in the inbox or trash
- • Task objects stored in mail folders
- • Other non-email content types
Don't Worry
These items may be migrated through their proper destination folders. Calendar appointments appear correctly in calendar views, tasks appear in task folders, etc.
Duplicate Detection Prevents Double Migration
How Deduplication Works
The platform employs incremental and delta migration passes that detect previously migrated messages using message IDs.
Example Scenario
When you send a message to a group you belong to, the email creates copies in both SentItems and Inbox. The system migrates it only once, preventing unnecessary duplication in the destination mailbox.