title: Click once deployment: Downloading XXX.manifest did not succeed. (404) Not Found
body: <p>One of our customers is having and issue updating their ClickOnce application after the deployment of a new version (upgrade from version 2 to version 3).</p>
  
  <p>First of all, when he ran the application, it didn't seem to detect that a new version had been deployed. Later on, after downloading manually the latest AssemblyName.application file from the Application Server (from the URL the application has been published to) he got the following error where, for some reason, it seems to keep looking for the old deployment (which doesn't exist anymore because it's been replaced by the new). The "funny" thing is that we've installed this version from different machines &amp; locations and it has worked fine for everybody except the 2 guys "behind that proxy". This is the error message they're getting:</p>
  
  <hr>
  
  <pre><code>ERROR SUMMARY
      Below is a summary of the errors, details of these errors are listed later in the log.
      * Activation of example.com/YYY/Client/AppName.application resulted in exception. Following failure messages were detected:
          + Downloading example.com/YYY/Client/Application Files/AppName_2_0_0_0/AppName.exe.manifest did not succeed.
          + The remote server returned an error: (404) Not Found.
  
  COMPONENT STORE TRANSACTION FAILURE SUMMARY
      No transaction error was detected.
  
  WARNINGS
      There were no warnings during this operation.
  
  
  ERROR DETAILS
      Following errors were detected during this operation.
      [22/03/2016 08:59:18] System.Deployment.Application.DeploymentDownloadException (Unknown subtype)
          - Downloading example.com/YYY/Client/Application Files/AppName_2_0_0_0/AppName.exe.manifest did not succeed.
          - Source: System.Deployment
          - Stack trace:
              at System.Deployment.Application.SystemNetDownloader.DownloadSingleFile(DownloadQueueItem next)
              at System.Deployment.Application.SystemNetDownloader.DownloadAllFiles()
              at System.Deployment.Application.FileDownloader.Download(SubscriptionState subState)
              at System.Deployment.Application.DownloadManager.DownloadManifestAsRawFile(Uri&amp; sourceUri, String targetPath, IDownloadNotification notification, DownloadOptions options, ServerInformation&amp; serverInformation)
              at System.Deployment.Application.DownloadManager.DownloadApplicationManifest(AssemblyManifest deploymentManifest, String targetDir, Uri deploymentUri, IDownloadNotification notification, DownloadOptions options, Uri&amp; appSourceUri, String&amp; appManifestPath)
              at System.Deployment.Application.ApplicationActivator.DownloadApplication(SubscriptionState subState, ActivationDescription actDesc, Int64 transactionId, TempDirectory&amp; downloadTemp)
              at System.Deployment.Application.ApplicationActivator.InstallApplication(SubscriptionState&amp; subState, ActivationDescription actDesc)
              at System.Deployment.Application.ApplicationActivator.PerformDeploymentActivation(Uri activationUri, Boolean isShortcut, String textualSubId, String deploymentProviderUrlFromExtension, BrowserSettings browserSettings, String&amp; errorPageUrl)
              at System.Deployment.Application.ApplicationActivator.ActivateDeploymentWorker(Object state)
          --- Inner Exception ---
          System.Net.WebException
          - The remote server returned an error: (404) Not Found.
          - Source: System
          - Stack trace:
              at System.Net.HttpWebRequest.GetResponse()
              at System.Deployment.Application.SystemNetDownloader.DownloadSingleFile(DownloadQueueItem next)
  
  COMPONENT STORE TRANSACTION DETAILS
      No transaction information is available.
  
  DETAILED EXECUTION FLOW
  ...
  [08:59:14] : DownloadQueueItem :  _sourceUri = example.com/YYY/Client/AppName.application,  _targetPath = D:\Users\UserName\AppData\Local\Temp\Deployment\MCX7AOC4.6KW\7E3KZCJY.P28.application
  [08:59:16] : HttpWebRequest= Proxy.IsByPassed=False, ProxyUri=http://BLAproxy.BLA.com:8080/
  [08:59:17] : HttpWebResponse=ResponseUri=example.com/YYY/Client/AppName.application
  [08:59:17] : Method Call : ManifestReader.FromDocumentNoValidation(D:\Users\UserName\AppData\Local\Temp\Deployment\MCX7AOC4.6KW\7E3KZCJY.P28.application) called.
  [08:59:17] : expectedAppId=example.com/YYY/Client/AppName.application#AppName.application, Version=2.0.0.0, Culture=neutral, PublicKeyToken=0e37c329267e5e4f, processorArchitecture=msil/AppName.exe, Version=2.0.0.0, Culture=neutral, PublicKeyToken=0e37c329267e5e4f, processorArchitecture=msil, type=win32
  [08:59:17] : Reparse the deployment manifest for validations.
  [08:59:17] : Method Call : ManifestReader.FromDocument(D:\Users\UserName\AppData\Local\Temp\Deployment\MCX7AOC4.6KW\7E3KZCJY.P28.application) called.
  [08:59:17] : Schema validation passed.
  [08:59:17] : Manifest is parsed successfully.
  [08:59:17] : Semantic validation passed.
  [08:59:18] : Signature validation passed.
  [08:59:18] : Method Call : FollowDeploymentProviderUri called.
  [08:59:18] : Deployment manifest zone is not local machine. Zone = Internet
  [08:59:18] : providerUri=example.com/YYY/Client/AppName.application,sourceUri=example.com/YYY/Client/AppName.application
  [08:59:18] : Deployment provider not followed.
  [08:59:18] : Processing of deployment manifest has successfully completed.
  [08:59:18] : Could not find application in store. Continue with downloading application manifest.
  [08:59:18] : Method Call : InstallApplication called.
  [08:59:18] : Method Call : DownloadApplication called.
  [08:59:18] : Start processing application manifest.
  [08:59:18] : Method Call : DownloadApplicationManifest called.
  [08:59:18] : Method Call : DownloadManifest called.
  [08:59:18] : Method Call : DownloadManifestAsRawFile called.
  [08:59:18] : Method Call : DownloadSingleFile called
  [08:59:18] : DownloadQueueItem :  _sourceUri = example.com/YYY/Client/Application Files/AppName_2_0_0_0/AppName.exe.manifest,  _targetPath = D:\Users\UserName\AppData\Local\Temp\Deployment\YLJO3ZJO.CAB\T2LP22AQ.EZX\AppName.exe.manifest
  [08:59:18] : HttpWebRequest= Proxy.IsByPassed=False, ProxyUri=http://BLAproxy.BLA.com:8080/
  </code></pre>
  
  <hr>
  
  <p>Does anybody have an idea of what might have occurred? We have some suspicions but, as I wouldn't like to condition your answers, I won't mention them for now.</p>
  
  <p>Thanks in advance for your help!!!</p>