Example: Run three Full Imports after deleted a user from Active Directory. After the third import the user is shown in "Missing from import". Run a two Full Imports after deleting another user from Active Directory. Then run an Incremental Import. Then run another Full Import. The user is not shown in the missing from Import.
If you are familiar with backup or index scheduling you might assume you should schedule a Full job once a day and an Incremental job several times a day. This won’t work correctly for SharePoint if you want to remove deleted users from the profile database.
This behavior is not documented in the Resource Kit or the SharePoint Portal Server admin guide. As a workaround, I’ve been manually running three consecutive Full Imports to clean up the deleted profiles. I’ve tested this on several servers both SPS SP1 and SPS SP2.