Blacklist File - microsoft/emat GitHub Wiki
Blacklist file
Entry included in this file will be filtered out from the Groups Calculation. This is usually useful if you have service account (like besadmin) or administrators that have permissions on all mailboxes and that will link all the mailboxes. Standard Exchange and Lync groups are filtered out by default.
The file will looks like (csv fomat to be placed in the ExportData folder):
Identity
Blacklist
[email protected]
contoso\blacklist
As reported in bug #5, Blacklist file is case-sensitive, please compile it including all possible way of representing a mailbox/samaccountname/email address. This issue will be fixed in the next tool release.