How to manually add a Security Identifier (SID) to a GFI MailEssentials access control list ( ONLY)

Answer

1. Navigate to the ..\MailEssentials\Wwwconf\DebugLogs\SID.log file
2. Check the SID (Security Identifier) from the last login that the administrator used; usually this will be another administrator account and it will end in '-500' or '-512'
3. Add this SID to the file Usermanagement.xml (taken from the directory MailEssentials\EmailSecurity\Data\) in this format: (starting with GFI MailEssentials Release 2 the location is now \GFI\MailEssentials\Attendant\data\Usermanagement.xml) 

1. Replace the SID with the customer's SID from the SID.log
2. Switch the mode of GFI MailEssentials to Local mode and then back to IIS mode