MSSQL Error 'The underlying provider failed on Open'

Question

I was using an .mdf for connecting to a database and entityClient. Now I want to change the connection string so that there will be no

Answer 1

I had the same issue few days ago, using "Integrated Security=True;" in the connection string you need to run the application pool identity under "localsystem" Sure this is not recommended but for testing it does the job.

This is how you can change the identity in IIS 7: http://www.iis.net/learn/manage/configuring-security/application-pool-identities