Fix ClickOnce application not launching

The Office 365 Hybrid Configuration Wizard uses the ClickOnce as deployment technology. While this is great, there are a lot of problems. For example, the ClickOnce application is not launching, or the ClickOnce application cannot be started error. While this should be an easy process, it takes a lot of frustration for most of us. You want the ClickOnce application to start, nothing more. In this article, you will learn how to fix ClickOnce application not launching.

ClickOnce

ClickOnce is a deployment technology that enables you to create self-updating Windows-based applications that can be installed and run with minimal user interaction.

The web browser Internet Explorer works out of the box with ClickOnce. You only have to set the .application to open with Internet Explorer so it can start as shown here: Office 365 Hybrid Configuration Wizard can’t start.

But sometimes, it doesn’t work with Internet Explorer, and you can’t start the application. Also, Internet Explorer went out of support on June 15, 2022. So you might not have Internet Explorer running on the machine.

ClickOnce application cannot be started

If you have run the Hybrid Configuration Wizard, you can uninstall it from Programs and Features in Control Panel. Nothing will happen to the configuration because it already applied the settings in Exchange on-premises and Exchange Online.

Open the web browser of your choice and go to https://aka.ms/HybridWizard.

It will download the RunOnce .application file.

Open the downloaded .application file, and it will show: Application cannot be started. Contact the application vendor.

Sometimes nothing happens.

So how do we get the RunOnce application to work? Let’s look at that in the next step.

How to start ClickOnce application

Step 1. Install the ClickOnce browser extension.

Find the extension on the add-on webpage for that browser:

• Mozilla Firefox: Breez ClickOnce
• Google Chrome: Meta4 ClickOnce Launcher

In this example, we will search for Breez ClickOnce extension and click on Add to Firefox.

Step 2. Click Add to install the extension.

Step 3. Click on the downloads icon and click on breezclickoncehelper.exe.

Step 4. Click on More info.

Step 5. Click Run anyway.

Step 6. The Breez ClickOnce Helper was installed successfully. Click OK.

Step 7. Go to Programs and Features and verify that Breez ClickOnce Helper appears in the installed list.

Step 8. Close all the web browsers.

Step 9. Start the Firefox browser and insert the URL https://aka.ms/HybridWizard.

Step 10. The Application Install window shows up, and you can click on Install.

That’s it!

Every time you need to open the RunOnce application, copy-paste the URL https://aka.ms/HybridWizard into your favorite browser, and it will start the application immediately because it’s already installed.

Read more: Export Office 365 mailbox to PST »

Conclusion

You learned how to launch ClickOnce applications easily in every browser of your choice. First, install the ClickOnce extension and the installer. After that, ensure that you close the browser. Finally, start the browser and visit the URL to run the RunOnce application.

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