title: VS 2008: Launching Silverlight Apps in Debugger: Various Random Errors
body: <p>We have been getting a range on infuriating error dialogs using Visual Studio 2008 SP1 when debugging our solution which is a 38 project solution with a group of Silverlight 3.0 projects. These errors are seemlingly random, but they are getting so frequent that it is a serious productivity problem now: I have been starting to get my solution running here for the last hour when I should be cutting code.</p>
  
  <p>There are various errors that pop up when debugging is launched. We have about 8 console apps and one Silverlight 3.0 app that is running in IE6.0.  We are using WCF Services and I have Resharper 4.5 installed.</p>
  
  <p>The first is:</p>
  
  <p>"Unable to start program '<a href="http://localhost:1799/XXXXXXXXXXXX.aspx" rel="nofollow noreferrer">http://localhost:1799/XXXXXXXXXXXX.aspx</a>'
  System call Failed."</p>
  
  <p>Debugging does not automatically stop, but when I click stop it will eventually come up with an error:</p>
  
  <p>"The debugger was unable to terminate one or more processes:
  "WebDev.WevServer.EXE: The debugger is still attaching to the process.
  The debugger may be unstable now. It is reccomended that you save all your files and exit."</p>
  
  <p>Sometimes the message does not tell you what it is it cannot detach from. In Process Explorer I can see that two WebDev.WevServer.EXE exist under the devenv.exe process. When I kill VS, these remain behind even when devenv.exe is gone...</p>
  
  <p>Why does this happen and why is there two of these processes? I don't come from a web development backgound...what are these processes?  IIS substitutes?</p>
  
  <p>The second error is:</p>
  
  <p>"Unable to start program '<a href="http://localhost:1799/XXXXXXXXXXXX.aspx" rel="nofollow noreferrer">http://localhost:1799/XXXXXXXXXXXX.aspx</a>'
  OLE has sent a request and is waiting for a reply."</p>
  
  <p>When I attempt to stop debugging, VS pops up a dialog telling me that the debugger has not completed, but I can attempt to force it to stop.  Selecting yes eventually allows it to stop gracefully.</p>
  
  <p>There are variations on these: sometimes the IEXPLORE.EXE process will start but end up not under devenv.exe in the Process Explorer tree and it has to be killed manually. Other times VS will tell me it is waiting for a long operation to complete and asks if I want to switch tasks, but nothing is actually clickable and devenv.exe has to be manually killed.  I am less concerned about this one as it is less frequent.</p>
  
  <p>This is REALLY becomming an issue for us, and the last thing I need is 4 out of 5 attempts to debug needing a VS restart.  Some developers in the team are restarting 20+ times a day...</p>
  
  <p>Any help appreciated...</p>