I don't believe it treats it any differently. In other words, it will
find the AD object and update it.

Also keep in mind, that before Portal will mark the profile for
deletion, it has to complete 3 consectutive "FULL" crawls of the profile
database, and any incremental crawl will reset that counter. This is
slightly different than crawling other data, where an incremental does
not restart the 3 strikes and you're out counter.

I had no idea about the "incremental crawl"
resetting the counter.. this sure explains alot.

so by mixing fulls and incrementals together during the week (Ex.
M-Full, Tue-Inc, W-Inc, TH-Full, FRI-Inc) you are pretty much
guaranteed never to get any profiles in the "MISSING" category whethere
the account has been gone 3 days or 3 months?

Correct, Also check out Michael Bollhoefer's response he just made where
he provides an LDAP filter to filter out the disabled accounts

You need to exclude disabled accounts or
rather include only active accounts through an LDAP filter on your
manage connections page for the profile import. The filter you will
need to implement is (&(objectCategory=person)(objectClass=user)( !
(userAccountControl:1.2.840.113556.1.4.803:=2))).

Further, the magic 3 imports is FULL imports not incremental. You
will need to do 3 full imports to exclude people into the missing
from import. Further, you might need to clean your profile manually
the first time to get all of the old accounts out.

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