Can't install or open Exchange Server Hybrid Configuration Wizard (HCW)

Symptoms 

After you install the Hybrid Configuration Wizard (HCW) through the Exchange Admin Center (EAC) or by downloading the wizard through https://aka.ms/HybridWizard, you’re prompted to open the ClickOnce application file. However, the Open command doesn’t open any window. When this issue occurs, you don’t receive any error message.

Cause 

The .application file extension that’s used by ClickOnce packages is no longer linked to the ClickOnce Application Deployment Support Library. This change causes a missing or misconfigured handler condition that prevents Windows from opening the HCW ClickOnce package.

Resolution 

Reassociate the .application file type with the ClickOnce Application Deployment Support Library, and then reinstall or open the HCW. 

1. Close all the open browser windows.

2. Create an empty text file on the server and name it Temp.application.

3. Right-click Temp.applicaton, and then select Open with > Choose another app.

4. Select Notepad, select the Always use this app checkbox, and then select OK.

5. Repeat step 3, select ClickOnce Application Deployment Support Library and Always use this app and set it as the default application.

6. Delete Temp.application, reopen your browser, and then try again to open the HCW through https://aka.ms/HybridWizard. The HCW should now install and open as expected.