Opening a page with an undefined control template crashes on iOS only when not debugging

Description

I have a content page like this

<ContentPage
    ...
    ControlTemplate="{StaticResource NonExistantTemplate}">
    ...
</ContentPage>

while debugging, the control template fails to load and the page still opens fine, even on a physical device. launching without the debugger attached causes the crash when opening the page.

I don't see anything in the logs mentioning the missing control template, and there's no intellisense or build errors for it either. That's probably going to be more generally useful than fixing this bug directly.

Steps to Reproduce

Create a content page that references a nonexistant control template as described above

Debug build to an iphone simulator

Stop debugging

Relaunch the app

Open the page

Link to public reproduction project repository

No response

Version with bug

9.0.0-preview.6.24327.7

Is this a regression from previous behavior?

Not sure, did not test other versions

Last version that worked well

Unknown/Other

Affected platforms

iOS

Affected platform versions

Simulator iPhone 15 iOS 17.2

Did you find any workaround?

No response

Relevant log output

No response

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I can repro this issue at iOS platform on the latest 17.11.0 Preview 5.0 (9.0.0-preview.6.24327.7 & 9.0.0-preview.5.24307.10 & 8.0.61). MauiApp4.zip

We throw here, but I wonder if we don't need to:

maui/src/Controls/src/Core/Window/Window.cs

Line 389 in 491c227

Page ?? throw new InvalidOperationException("No page was set on the window.");

I've faced the same problem.
I find it hard to understand why this isn't fixed as it's a single and debatable line. What is the benefit of throwing over ignoring? If this is a dynamically loaded / bound and interchangeable element it will load late, causing this issue. And, during a 'change' will at some point be null.

My workaround is to use a content view and embed it inside the page.

[Android, iOS] Throw exceptions consistently for invalid StaticResour…

March 30th, Inflight Candidate (#34617)

[iOS] Fix StaticResource Hot Reload crash on iOS (#35020)

[Testing] Fixed test failure in PR 35234 - [05/08/2026] Candidate (#3…

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Opening a page with an undefined control template crashes on iOS only when not debugging #23903

Description

Steps to Reproduce

Link to public reproduction project repository

Version with bug

Is this a regression from previous behavior?

Last version that worked well

Affected platforms

Affected platform versions

Did you find any workaround?

Relevant log output

Closed similar issues:

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Opening a page with an undefined control template crashes on iOS only when not debugging #23903

Description

Description

Steps to Reproduce

Link to public reproduction project repository

Version with bug

Is this a regression from previous behavior?

Last version that worked well

Affected platforms

Affected platform versions

Did you find any workaround?

Relevant log output

Activity

github-actions commented on Jul 29, 2024

Closed similar issues:

kevinxufei commented on Jul 30, 2024

mattleibow commented on Jul 30, 2024

thales-man commented on Nov 28, 2025

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