Entity Framework The underlying provider failed on Open

Question

Below is my connection string:

connectionString=\"metadata=res://*/EDMX.Test.csdl|res://*/EDMX.Test.ssdl|res://*/EDMX.Test.msl;provider=System.Data.Sq

Answer 1

If you are using a local .mdf file, probably a sync software such Dropbox attempted to sync two log files (.ldf) in two different computers you can delete the log files from the bin Directory and make sure the .mdf properties->Copy to Output Directory ->Copy if newer that will copy the selected DB file and it's log to the bin Directory. !Alert- if your DB file has only changed in the bin Directory all the changes ill be discarded!