I work with a friend using SVN.
I downloaded his solution and tried to add connection to DB via server explorer
(using mdf file).
He is using SQLExpress and I use SQL SMSS.
my advanced settings are:
Data Source=.\SQLEXPRESS;AttachDbFilename="C:\Users\elad\Documents\Visual Studio 2010\Projects\SVN\UGI\Ugi\Ugi.mdf";Integrated Security=True;Connect Timeout=30;User Instance=True
I got this error. What am I doing wrong?

Sql Serverinstance installed on your machine?Data Source=[Your friends pc name]\SqlExpress..\SqlExpressmeans connect to the instanceSqlExpresson the local machine.I am guessing it’s more likely to be point #1 but could be the others as well.
hth