Hybrid Update Agent download fails

No, unfortunately this is bad coding to make this dependency. TBH the needed hybridagentinstaller.msi is from 2019. 

I installed the MSHybridService.msi via  https://aka.ms/hybridagentinstaller.

Then I started the HCW again and it wants to update itself. Unfortunately, this fails.

[...]
ERROR SUMMARY
	Below is a summary of the errors, details of these errors are listed later in the log.
	* Activation of C:\Users\xxxxx\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Microsoft Corporation\Microsoft Office 365 Hybrid Configuration Wizard.appref-ms| resulted in exception. Following failure messages were detected:
		+ Downloading https://hybridconfigwizard.azurewebsites.net/ClickOnce/Application Files/Microsoft.Online.CSE.Hybrid.Client_17_1_3902_0/ko/Microsoft.Online.CSE.Hybrid.Resource.resources.dll.deploy did not succeed.
		+ The remote server returned an error: (404) Not Found.
[...]
ERROR DETAILS
	Following errors were detected during this operation.
	* [19.11.2025 08:22:49] System.Deployment.Application.DeploymentDownloadException (Unknown subtype)
		- Downloading https://hybridconfigwizard.azurewebsites.net/ClickOnce/Application Files/Microsoft.Online.CSE.Hybrid.Client_17_1_3902_0/ko/Microsoft.Online.CSE.Hybrid.Resource.resources.dll.deploy 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, X509Certificate2 clientCertificate)
			at System.Deployment.Application.DownloadManager.DownloadDependencies(SubscriptionState subState, AssemblyManifest deployManifest, AssemblyManifest appManifest, Uri sourceUriBase, String targetDirectory, String group, IDownloadNotification notification, DownloadOptions options)
			at System.Deployment.Application.ApplicationActivator.DownloadApplication(SubscriptionState subState, ActivationDescription actDesc, Int64 transactionId, TempDirectory& downloadTemp)
			at System.Deployment.Application.ApplicationActivator.InstallApplication(SubscriptionState& subState, ActivationDescription actDesc)
			at System.Deployment.Application.ApplicationActivator.ConsumeUpdatedDeployment(SubscriptionState& subState, ActivationDescription actDesc)
			at System.Deployment.Application.ApplicationActivator.PerformDeploymentUpdate(SubscriptionState& subState, String& errorPageUrl)
			at System.Deployment.Application.ApplicationActivator.ProcessOrFollowShortcut(String shortcutFile, String& errorPageUrl, TempFile& deployFile)
			at System.Deployment.Application.ApplicationActivator.PerformDeploymentActivation(Uri activationUri, Boolean isShortcut, String textualSubId, String deploymentProviderUrlFromExtension, BrowserSettings browserSettings, String& errorPageUrl, Uri& deploymentUri)
			at System.Deployment.Application.ApplicationActivator.PerformDeploymentActivationWithRetry(Uri activationUri, Boolean isShortcut, String textualSubId, String deploymentProviderUrlFromExtension, BrowserSettings browserSettings, String& errorPageUrl)
--- End of stack trace from previous location where exception was thrown ---
			at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
			at System.Deployment.Application.ApplicationActivator.PerformDeploymentActivationWithRetry(Uri activationUri, Boolean isShortcut, String textualSubId, String deploymentProviderUrlFromExtension, BrowserSettings browserSettings, String& 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)

Hi Lukas, great that you are already on it. But the hybrid agent installer itself doesn't help us, does it?

So the HCW will still abort at this point. Or is it possible to place the MSI at the right location, so that the HCW will recognize the downloaded file?

I already tried this yesterday with the temp folder location under %appdata%