Finding schema differences

by Mitch Tulloch [Published on 6 Nov. 2007 / Last Updated on 6 Nov. 2007]

How to find schema differences between two forests.

Here's an interesting issue one consultant told me about. He had heard that a company wanted to migrate some user and computer accounts from one Active Directory forest to another forest. So far so good, right? But the original (first) forest had had some modifications made to its AD schema to extend the schema in order to support several third-party applications, and unfortunately the documentation on what modifications had been made to the schema were…let's say…sorely lacking.

The company wanted to know if there was some way of finding out what differences there were between the schema of the original forest and the schema of the new forest. After some searching around, the consultant came up with Schema Analyzer, a tool included with ADAM (Active Directory in Application Mode) and using this tool the company could compare the two schemas and determine which classes and attributes were present in the original schema that were not present in the new schema. Then the company could use this information to create the necessary classes and attributes in the new schema.

For more information about Schema Analyzer and ADAM, see Introducing ADAM.


Mitch Tulloch is lead author for the Windows Vista Resource Kit from Microsoft Press, which is THE book for IT pros who want to deploy, maintain and support Windows Vista in mid- and large-sized network environments. Mitch is also the author of Introducing Windows Server 2008, the first book from Microsoft Press about the exciting new server platform. For more information on these and other books written by Mitch, see

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The Author — Mitch Tulloch

Mitch Tulloch is a well-known expert on Windows Server administration and cloud computing technologies. He has published over a thousand articles on information technology topics and has written, contributed to or been series editor for over 50 books.

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