Silverlight – Install Failed Error code 1603 & Event ID 11606 Could not Access Network Location

This issue has been seen with a network based install that was no longer available. Steps tested were uninstall and install newer versions and lastly backing up registry and deleting key for Silverlight. Bob Pomeroy has posted a clean up utility back in 2008 but fixes issues with newer versions. After running that utility install of Silverlight 5 worked great.

http://blogs.msdn.com/b/rpomeroy/archive/2008/06/10/how-to-manually-clean-up-a-bad-silverlight-installation.aspx

 

You may also want to look into this post

http://forums.silverlight.net/t/249269.aspx/1?How+To+Fix+Silverlight+install+failure+at+99+code+1603+or+generic+Unknown+Error