When deploying schema's and related maps to BizTalk Server 2010, you may receive the following error when undeploying the map:
Schema referenced by Map "*****" has been deleted. The local, cached version of the BizTalk Server group configuration is out of date. You must refresh the BizTalk Server group configuration before making further changes.
Me and a colleague discovered that this may be related to the Map project and the Schema project sharing the same .Net namespace.
When we deploy a solution that has 1 single namespace like company.application for all projects, we always encounter this error.
When we deploy solutions that have different namespaces per project, like company.application.schemas and company.application.maps, this will not occur.
This behaviour (bug?) is different from behaviour in BizTalk 2004 and 2006R2. I have not tested this in BizTalk 2009.
To remedy this problem, manualy undeploy the maps first, than the schemas.
If you have schemas and maps in a single project (not a best practice) you also have no problems.