The most funny in this question is that 49.9% of answers given so far were "wrong" and only 6.8% were "right".. 1000 lemmings can't be wrong

may be start by analysing the problem from SQL Profiler - it can catch all requests to database from EM, then look what part of "opening process" takes the most...

And if the SQL Server runs under a local account (not domain account) - which permissions shall I give on the network share to allow acces?