Blazor Unified Web App Core 8 : base href not working properly when properly configured

[vsfeedback]

This issue has been moved from a ticket on Developer Community.

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[severity:It’s more difficult to complete my work]
in Blazor Unified Web App, let’s suppose your web sit under a subdirectory, then you need to set many things (hope Microsoft could simplify that in a next version.
So Currently, my app sit in https://prototypeomega.ca/Allergy
because it need to be under a subdirectory (Allergy) here the settings we need to set

In App.Razor:
<base href=“/Allergy/” />

In Program.cs:
app.UsePathBase(“/Allergy”);

In launchSettings.json (for Local run):
add “launchUrl”: “Allergy/”
to http, https and IIS Express

now, if you’re using Identity, Account/Page/manage/index.razor will crash upon opening.
You need to change the @page from @page “/Account/Manage” to @page “/Allergy/Account/Manage”
All other page will work BUT, if you press F5 on a page, it will also crash just like Manage/index.
you’ll need to also add the prefix /Allergy to all your page.
Furthermore, if you REMOVE the base page (without the Allergy) it will not work.
This is a bug because there should be only 1 page directive.

The bug in action can be seen in the video I made.
[https://youtu.be/aV8_y7MehGQ](Youtube Video Showing the bug in action)

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Original Comments

Feedback Bot on 11/10/2025, 03:17 AM:

We have directed your feedback to the appropriate engineering team for further evaluation. The team will review the feedback and notify you about the next steps.

Patrice Charbonneau on 11/11/2025, 02:18 AM:

(private comment, text removed)

[Sigma3Wolf]

I already reported to Microsoft the problem was caused by a missing app.UseRouting();
before they moved the ticket this morning, I confirm this ticket can be closed, although as specified in my last message, I found strange that a missing instruction cause the program to work properly on some page and not work properly on other razor component.
The problem should be there or not, but not both at same time depending of the component used.

Nevertheless, app.UseRouting(); fixed the problem