While Testing Search Configuration in SharePoint 13 I was unable to start the crawler as well as Search Application Topology was showing error that it has not been enabled.  After a bit of binging find out a Forum Answer by Microsoft Search Product team.  Solution is simple install these 4 hotfixes on your Search Server.

For Detailed Information about error and Microsoft Reply.

http://social.technet.microsoft.com/Forums/en-US/sharepointitpropreview/thread/50acc2b8-dd56-4d5a-a660-dffa325ef807/

for Quick Fix:

http://hotfixv4.microsoft.com/Windows%207/Windows%20Server2008%20R2%20SP1/sp2/Fix402568/7600/free/447698_intl_x64_zip.exe

http://hotfixv4.microsoft.com/Windows%207/Windows%20Server2008%20R2%20SP1/sp2/Fix368051/7600/free/433385_intl_x64_zip.exe

http://hotfixv4.microsoft.com/Windows%207/Windows%20Server2008%20R2%20SP1/sp2/Fix354400/7600/free/427087_intl_x64_zip.exe

+

http://www.microsoft.com/en-us/download/details.aspx?id=27060

Source: Paul Stork Answer