Process: DefMgr.exe (Microsoft Default Manager)
from 
Stardock Forums
Stardock Forums
DefMgr.exe - General Information
Name:
DefMgr.exe (Microsoft Default Manager)
Publisher
Microsoft Corp.
Product:
Default Manager
Default location:
%ProgramFiles%\Microsoft\Search Enhancement Pack\Default Manager\DefMgr.exe
DefMgr.exe - Description and Recommendation
Belongs to Windows Live (messenger / mail / toolbar, etc). At this time it's not clear what it does.
DefMgr.exe - Uninstall Techniques