An attempt to attach an auto-named database for file failed

Question

i build a Web Site in Visual Studio 2010 and used the code for Memberships, Users and Roles etc that are stored in the ASPNETDB.mdf database file without any problems. Now im trying to deploy my ASP.NET Web Site on the network running the IIS7.5 im getting this Error:

An attempt to attach an auto-named database for file .mdf failed. A database with the     
same name exists, or specified file cannot be opened, or it is located on UNC share.

Below is my connection string for the database:

<connectionStrings>
   <add name="KBDConnectionString" connectionString="data source=.\SQLEXPRESS;Integrated  
        Security=SSPI;AttachDBFilename=|DataDirectory|\KBD.mdf;User Instance=true" 
        providerName="System.Data.SqlClient" />
</connectionStrings>

im gratefull for your help

here is my website config (IIS Folder):

<?xml version="1.0" encoding="UTF-8"?>
 <configuration>
   <connectionStrings>
     <add name="KBDConnectionString" connectionString="data source=.\SQLEXPRESS;  
                Integrated Security=SSPI;AttachDBFilename=|DataDirectory|KBD.mdf;User 
                Instance=true" providerName="System.Data.SqlClient" />
   </connectionStrings>
   <system.web>
      <httpHandlers>
       <add path="ImgRequest.ashx" verb="*" type="Syncfusion.Web.UI.WebControls.Diagram.NodeRenderHandler,Syncfusion.Diagram.Web, Version=10.404.0.71, Culture=neutral, PublicKeyToken=3d67ed1f87d44c89" />
  <add path="PaletteImgRequest.ashx" verb="*" type="Syncfusion.Web.UI.WebControls.Diagram.ThumbNodeRenderHandler,Syncfusion.Diagram.Web, Version=10.404.0.71, Culture=neutral, PublicKeyToken=3d67ed1f87d44c89" />
  <!--<add path="OverviewImgRequest.ashx" verb="*" type="Syncfusion.Web.UI.WebControls.Diagram.OverviewDocumentRenderHandler,Syncfusion.Diagram.Web, Version=10.404.0.71, Culture=neutral, PublicKeyToken=3d67ed1f87d44c89"/>-->
</httpHandlers>
<compilation debug="true" targetFramework="4.0">
  <assemblies>
    <add assembly="Syncfusion.Tools.Web, Version=10.404.0.71, Culture=neutral, PublicKeyToken=3D67ED1F87D44C89" />
    <add assembly="Syncfusion.Shared.Web, Version=10.404.0.71, Culture=neutral, PublicKeyToken=3D67ED1F87D44C89" />
    <add assembly="System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A" />
    <add assembly="System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
    <add assembly="Syncfusion.Core, Version=10.404.0.71, Culture=neutral, PublicKeyToken=632609B4D040F6B4" />
    <add assembly="Syncfusion.Shared.Base, Version=10.404.0.71, Culture=neutral, PublicKeyToken=3D67ED1F87D44C89" />
    <add assembly="Syncfusion.Grid.Base, Version=10.404.0.71, Culture=neutral, PublicKeyToken=3D67ED1F87D44C89" />
    <add assembly="Syncfusion.Tools.Base, Version=10.404.0.71, Culture=neutral, PublicKeyToken=3D67ED1F87D44C89" />
    <add assembly="Syncfusion.Diagram.Web, Version=10.404.0.71, Culture=neutral, PublicKeyToken=3D67ED1F87D44C89" />
    <add assembly="Syncfusion.Diagram.Base, Version=10.404.0.71, Culture=neutral, PublicKeyToken=3D67ED1F87D44C89" />
    <add assembly="System.Runtime.Serialization.Formatters.Soap, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A" />
    <add assembly="Syncfusion.Diagram.Windows, Version=10.402.0.71, Culture=neutral, PublicKeyToken=3D67ED1F87D44C89" />
    <add assembly="Syncfusion.Compression.Base, Version=10.404.0.71, Culture=neutral, PublicKeyToken=3D67ED1F87D44C89" />
    <add assembly="Syncfusion.Pdf.Base, Version=10.404.0.71, Culture=neutral, PublicKeyToken=3D67ED1F87D44C89" />
  </assemblies>
</compilation>
<authentication mode="Forms">
  <forms loginUrl="~/Account/Login.aspx" timeout="2880" />
</authentication>
<membership defaultProvider="KBDSqlMembershipProvider">
  <providers>
    <clear />
    <add name="KBDSqlMembershipProvider" type="System.Web.Security.SqlMembershipProvider" connectionStringName="KBDConnectionString" enablePasswordRetrieval="false" enablePasswordReset="true" requiresQuestionAndAnswer="false" requiresUniqueEmail="false" passwordFormat="Hashed" maxInvalidPasswordAttempts="5" minRequiredPasswordLength="6" minRequiredNonalphanumericCharacters="0" passwordAttemptWindow="10" applicationName="KrallmannBusinessDesigner" />
  </providers>
</membership>
<profile defaultProvider="KBDSqlProfileProvider">
  <providers>
    <clear />
    <add name="KBDSqlProfileProvider" type="System.Web.Profile.SqlProfileProvider" connectionStringName="KBDConnectionString" applicationName="KrallmannBusinessDesigner" />
  </providers>
  <!--<properties>
    <add name="UserName" type="String"/>
    <add name="Email" type="String" />
  </properties>-->
</profile>
<roleManager enabled="false">
  <providers>
    <clear />
    <add name="AspNetSqlRoleProvider" type="System.Web.Security.SqlRoleProvider" connectionStringName="ApplicationServices" applicationName="/" />
    <add name="AspNetWindowsTokenRoleProvider" type="System.Web.Security.WindowsTokenRoleProvider" applicationName="/" />
  </providers>
</roleManager>
<customErrors mode="Off"/>
</system.web>
<system.webServer>
<modules runAllManagedModulesForAllRequests="true" />
    <validation validateIntegratedModeConfiguration="false" />
    <defaultDocument>
        <files>
            <add value="Account/Login.aspx" />
        </files>
    </defaultDocument>
</system.webServer>
</configuration>

Answer 1

Check connection string. Correct way (as mentioned in MSDN article reffered by @Devjosh):

"AttachDBFilename=|DataDirectory|xxxxxx.mdf;User Instance=true"

Your code:

AttachDBFilename=|DataDirectory|**\**KBD.mdf

Backslash is not needed.