Edge Not Used for Authentication Flow When Set as Default Browser (MSAL Falls Back to WebView) #2414
Description
When a specific browser is configured in auth_config.json and Microsoft Edge is set as the default browser on the device, MSAL does not launch Edge for the authentication flow.
Instead, a WebView is opened.
However, when Firefox or Chrome is set as the default browser, the external browser is launched correctly.
MSAL logs indicate that Edge is not recognized as a trusted browser.
Smartphone
Device: Google Pixel 9 Pro
Android Version: Android 16
Browser: Microsoft Edge (installed via Google Play Store Version 142.0.3595.107)
MSAL Version: 8.1.1
Stacktrace / Logs
Relevant log messages:
Browser: com.microsoft.emmx signature hash not match
No available browser installed on the device.
To Reproduce
Install Microsoft Edge from the Google Play Store
Set Edge as the default browser on the device
Configure auth_config.json to explicitly specify the browser
Trigger the MSAL login flow
Observe that MSAL opens a WebView instead of Edge
Comparison:
Default browser = Firefox → external browser opens correctly
Default browser = Chrome → external browser opens correctly
Only Edge triggers the fallback to WebView.
Expected behavior
MSAL should launch the Microsoft Edge browser when it is set as the default browser on the device.
Actual behavior
MSAL does not recognize Edge as a valid or trusted browser due to a signature mismatch:
Browser: com.microsoft.emmx signature hash not match
As a result, MSAL concludes that no compatible browser is installed and falls back to a WebView.
Additional context
Edge is installed normally via the Google Play Store.
Other browsers work as expected.
The error suggests that MSAL’s internal list of trusted browser signatures may be outdated or incorrect for the current version of Microsoft Edge.
This likely causes MSAL 8.1.1 to reject Edge as a trusted browser.