In Exchange 2000, the ADC schema files were a subset of the Exchange 2000
core schema files. So although the ADC’s setup /schemaonly switch extended
the schema, customers were required to perform further schema extensions
using setup /forestprep. This meant longer lockdown periods for larger
customers whose custom applications were sensitive to schema extensions due
to the delayed nature of replications and resetting of indexed attributes. (You
may refer to KB article 230662 for more information on indexed attributes)...