How do i install a click-once application from the browser

Question

For many years I have been developing and updating an application in VB.Net using 'click-once' in VS. I have only been able to install it using FireFox. Recently (since about a week ago) I have been unable to install or upgrade the application. There have been no changes to my development environment.

The upload of the application seems to work OK. And have confirmed all the files are available.

I usually get a 403 Forbidden error (when doing an install/upgrade) and checked with the server service provider. All OK there. I can download the files with CoreFTP and if I change the install path, cal install from a local drive.

This is a real pain as my customers are used to updating directly from the application (as they have done for many years.)

This is the error:

************** Exception Text **************

System.Deployment.Application.DeploymentDownloadException: Downloading http://jumbuckinfo.ipage.com/Jumbuck/Application Files/Jumbuck_1_37_2_89/Jumbuck.exe.manifest did not succeed. ---> System.Net.WebException: The remote server returned an error: (403) Forbidden.

Have you any idea what might have gone wrong?

Answer 1

Hello thanks for reaching out!

Step-by-step procedure to fix ClickOnce 403 and enable browser install

1. Open the .application link directly:   Go to your app’s public .application URL (e.g., http://yourdomain/YourApp/YourApp.application)"http://yourdomain/yourapp/yourapp.application)") and try installing.
2. Enable ClickOnce in Edge:   In Edge, turn on ClickOnce support (Settings > default browser features or enterprise policy), then retry the .application link.
3. Confirm required MIME types on the host:   Add these content types in your hosting control panel or web.config:
   • .application = application/x-ms-application
     • .manifest = application/x-ms-manifest
       • .deploy = application/octet-stream
         • .dll, .exe = application/octet-stream
         1. Test the failing manifest URL directly:   Open the exact URL from the error (e.g., …/Application Files/.../YourApp.exe.manifest). If it’s 403, the server is blocking it—fix hosting rules/permissions.
         2. Disable blocking features on the host:   Turn off hotlink protection, bot filters, or path rules; whitelist .application, .manifest, .deploy, .dll, .exe and your app’s folder.
         3. Check HTTPS and certificates:   Use a valid TLS certificate (correct hostname, full chain). Ensure the site does not require client certificates. Retry the install.
         4. Verify folder permissions and paths:   Ensure the deployment folder and files are publicly readable. Avoid unusual characters in paths and confirm “Application Files” is accessible.
         5. Republish with aligned URLs:   In Visual Studio, set Installation URL to the exact public URL users click. Republish, upload all files (including “Application Files”), and keep paths consistent.
         6. Clear the ClickOnce cache on a test machine:   Run: rundll32 dfshim CleanOnlineAppCache Relaunch the .application link.
         7. Try another modern browser with ClickOnce:   Test in Edge (recommended) and Chrome with the ClickOnce helper/setting enabled. Avoid relying on Firefox alone.
         8. Remove .deploy if your host mishandles it (optional):   In VS Publish Options, uncheck “Use .deploy file extension,” republish, and re-upload—some hosts mis-handle .deploy.
         9. Validate by full install and upgrade path:

• Fresh install from .application link.
• Trigger an in-app update and confirm it fetches the new “Application Files” version without 403.