Beware of HOSTS Entries

By | May 30, 2012


    • Can’t install Exchange service packs (PrepareAD / PrepareSchema do not run properly)
        • Setup encountered a problem while validating the state of Active Directory: Setup could not retrieve the schema master domain controller information from Active Directory.
    • Exchange database will not mount / dismounted
    • Errors in Event Log:
        • 9519 – The following error occurred while starting database Mailbox Database: 0x8004010f
    • DCDIAG is successful (other than event log issues)


The resolution in my particular situation was removing entries to the SBS server in the HOSTS file.  I’m not sure how they got there but once I removed any references to itself from the HOSTS file (other than, I was able to mount the database and run PrepareAD and PrepareSchema


I wish I could take credit for this but, as most of us IT guys are, I’m just an excellent researcher.  The following is an excerpt from this blog, which is where I found the fix:

I had Exact same error installing EX2007 SP1 on a test single DC lab.I resolved mine by removing the entry in the hosts file for the DC. Although the entry was correct and all seemed fine, the install finally got passed the error.
December 4th, 2009 2:44pm

Category: IT