I am configuring solar and lucen both together for different index (master and web ) in sitecore . I am using 4.1 solar and sitecore 8.1.
I've enable both Sitecore.ContentSearch.Solr.DefaultIndexConfiguration and Sitecore.ContentSearch.lucen.DefaultIndexConfiguration config and respective index config. while rebulding the index I am getting below error
Could not resolve type name: Sitecore.ContentSearch.SolrProvider.SolrSearchIndex, Sitecore.ContentSearch.SolrProvider (method: Sitecore.Configuration.Factory.CreateFromTypeName(XmlNode configNode, String[] parameters, Boolean assert)).
What are the possible causes for above error?
It means that Sitecore.ContentSearch.SolrProvider.dll is not in your bin directory.
Download Solr support package for your Sitecore version from dev.sitecore.net and copy dlls from it.