Why??? process cannot access the file because it is being used by another process

oh, also I look at the code as I walk thru it and the error I see is:

[0] = {System.Data.SqlClient.SqlError: Cannot open user default database. Login failed.}
[1] = {System.Data.SqlClient.SqlError: Login failed for user cpuname\username'.}

Please post your connection string.  I suspect you are trying to attach the database as opposed to merely opening it.

On second thoughts, does the default database for cpuname\username exist?  If not change it to a database that does exist, Master for example.

since I am using a sourcesafe I have to share the .mdf with the rest of the team, so I do have to keep attaching and detaching the mdf to check it in.  the default db was the db that we are using and I thought, well maybe behind the scenes this is causing problems, so I made the default db for the cpuname\username the Master Db, this way if I detach the db we are using it doesn't cause problems.

so to answer your question, the default db is Master.

I was told that linq doesn't look at the app.config file where the other connection string is. it has the same values either way.
this is from the Settings.settings file.

here is the connection string:

<?xml version='1.0' encoding='utf-8'?>
<SettingsFile xmlns="http://schemas.microsoft.com/VisualStudio/2004/01/settings" CurrentProfile="(Default)" GeneratedClassNamespace="example1.Core.Properties" GeneratedClassName="Settings">
  <Profiles />
  <Settings>
    <Setting Name="example1ConnectionString" Type="(Connection string)" Scope="Application">
      <DesignTimeValue Profile="(Default)"><?xml version="1.0" encoding="utf-16"?>
<SerializableConnectionString xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
        <ConnectionString>Data Source=.\SQLEXPRESS;AttachDbFilename="C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\Data\example1.mdf";Integrated Security=True;User Instance=True</ConnectionString>
  <ProviderName>System.Data.SqlClient</ProviderName>
</SerializableConnectionString></DesignTimeValue>
      <Value Profile="(Default)">Data Source=.\SQLEXPRESS;AttachDbFilename="C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\Data\example1.mdf";Integrated Security=True;User Instance=True</Value>
    </Setting>
  </Settings>
</SettingsFile>

whoops, one of my examples above says  db1.mdf, and the other has example1.mdf.

I obviously am just replacing the real name of the db to something I am making up.  they should be the same and in my code they are. so ignore this oversight.

>>since I am using a sourcesafe I have to share the .mdf with the rest of the team, so I do have to keep attaching and detaching the mdf to check it in.<<
Then that is your problem.  There is simply no need to do that.  I am surprised you have not corrupted the database yet.

why does it work for the rest of our web pages except for this one page? besides the fact the others don't use Linq and this one does?

we are all working remotely on our machines at our homes, and due to the situation we have to have a local install of the .mdf file.
I have to download the changes to the .mdf from the other users, and to do that, I must detach the db or it won't let me download a file becz it's in use.

any other workarounds?
and I keep thinking to myself, it works just fine with the other pages just fine, except for this one page that uses Linq.