title: documentdb emulator gatewayservice crashing on startup
body: <p>I was looking to learn about documentdb and installed the emulator seemingly without error. However, upon startup I have a service crashing:</p>
  
  <p>GatewayServiceStartup</p>
  
  <p>Judging from the title I am guessing it is an important service to the emulator. Interestingly enough it seems like the emulator continues to load and attempts to open :
  <a href="https://localhost:8081/_explorer/index.html" rel="noreferrer">https://localhost:8081/_explorer/index.html</a></p>
  
  <p>without success.</p>
  
  <p>using the command prompt I attempted to start the gateway services manually and here is the results:</p>
  
  <p>C:\Program Files\DocumentDB Emulator\Packages\GatewayService\GatewayService.Code>documentdb.gatewayservice.exe /?</p>
  
  <p>Unhandled Exception: System.Runtime.InteropServices.COMException: Invalid value for registry (Exception from HRESULT: 0x80040153 (REGDB_E_INVALIDVALUE))
     at System.Runtime.InteropServices.RuntimeEnvironment.GetDeveloperPath()
     at System.AppDomain.SetupFusionStore(AppDomainSetup info, AppDomainSetup oldInfo)
     at System.AppDomain.SetupDomain(Boolean allowRedirects, String path, String configFile, String[] propertyNames, String[] propertyValues)</p>
  
  <p>C:\Program Files\DocumentDB Emulator\Packages\GatewayService\GatewayService.Code>documentdb.startupentrypoint.exe /?</p>
  
  <p>Unhandled Exception: System.Runtime.InteropServices.COMException: Invalid value for registry (Exception from HRESULT: 0x80040153 (REGDB_E_INVALIDVALUE))
     at System.Runtime.InteropServices.RuntimeEnvironment.GetDeveloperPath()
     at System.AppDomain.SetupFusionStore(AppDomainSetup info, AppDomainSetup oldInfo)
     at System.AppDomain.SetupDomain(Boolean allowRedirects, String path, String configFile, String[] propertyNames, String[] propertyValues)</p>
  
  <p>C:\Program Files\DocumentDB Emulator\Packages\GatewayService\GatewayService.Code></p>
  
  <p>Is the gateway service relevant? Any idea how to fix? </p>
  
  <p>Quick Edit:
  I have followed the directions listed here:
  <a href="https://docs.microsoft.com/en-us/azure/documentdb/documentdb-nosql-local-emulator#troubleshooting" rel="noreferrer">https://docs.microsoft.com/en-us/azure/documentdb/documentdb-nosql-local-emulator#troubleshooting</a></p>
  
  <p>No etl file is generated to be emailed.</p>
  
  <p>Thanks in advance</p>