During deploying Lync 2013 pilot pool for side-by-side migration from Lync 2010, I faced with strange problem on Step 1 (AD Preparation) in Wizard.
I have had installed Lync 2010 in my infrastructure, so I have a “half-prepared” schema for Lync 2013 Server. To update your current schema Lync uses four ldf scripts , which you can find in your Lync installation disk (<drive letter>:\support\schema).
- ExternalSchema.ldf is is used for interoperability with Microsoft Exchange Server
- ServerSchema.ldf is the primary Lync Server 2013 schema file
- BackCompatSchema.ldf is used for interoperability with any components from prior releases
- VersionSchema.ldf is used for version information of the prepared schema
Wizard runs them in the following order :
- ExternalSchema.ldf
- ServerSchema.ldf
- BackCompatSchema.ldf
- VersionSchema.ldf
To resolve my problem I decided to run scripts manually on my DC
*don’t forget to change DC= and type FQDN of your DC
ldifde.exe -i -v -k -j "C:\Users\rlevchenko\AppData\Local\Temp" -f "D:\Support\Schema\ExternalSchema.ldf" -c DC=X "DC=demo,DC=local" -s ad.demo.local ldifde.exe -i -v -k -j "C:\Users\rlevchenko\AppData\Local\Temp" -f "D:\Support\Schema\ServerSchema.ldf" -c DC=X "DC=demo,DC=local" -s ad.demo.local ldifde.exe -i -v -k -j "C:\Users\rlevchenko\AppData\Local\Temp" -f "D:\Support\Schema\BackCompatSchema.ldf" -c DC=X "DC=demo,DC=local" -s ad.demo.local ldifde.exe -i -v -k -j "C:\Users\rlevchenko\AppData\Local\Temp" -f "D:\Support\Schema\VersionSchema.ldf" -c DC=X "DC=demo,DC=local" -s ad.demo.local
UseIT | Roman Levchenko 
Reblogged this on Sutoprise Avenue, A SutoCom Source.
Just got off a Microsoft Support Call, I had this same error and it was due to the Primary Domain Controller having memory resource issues. We also have Exchange 2010 running on it (not best practice and working on correcting) which was using up the resources.
MS Support – restarted DC, stopped a third party service that tied in with exchanged, and recycled all IIS exchange app pools.
Fixed.