Mono Runtime Attempts to Load Missing pt-BR Satellite Assemblies Causing Initialization Lag in MAUI App

[BrundhaVelusamy]

We’re encountering a recurring issue when running our .NET MAUI app on devices with pt-BR (Portuguese - Brazil) UI settings. Our project is defined with neutral language as en-US, and we do not include localized resource assemblies for pt-BR.

However, during InitializeComponent() execution, the Mono runtime attempts to load satellite assemblies like:

pt-BR/Syncfusion.Maui.Toolkit.resources.dll  
pt/Syncfusion.Maui.Toolkit.resources.dll

These assemblies do not exist in our app package, and we see repeated log entries like:

[monodroid-assembly] open_from_bundles: failed to load bundled assembly pt-BR/Syncfusion.Maui.Toolkit.resources.dll   
[monodroid-assembly] open_from_update_dir: assembly file DOES NOT EXIST

This causes noticeable lags and timeouts during initialization, even though the fallback to neutral resources eventually works.

We’ve tried setting:
CultureInfo.DefaultThreadCurrentUICulture = new CultureInfo("en-US");

But it didn’t resolve the issue.

• Is there a recommended way to suppress or prevent these unnecessary satellite assembly load attempts?
• Is this expected behavior in Debug builds, and will it be optimized in Release builds?
• Could this be related to how MAUI or Mono handles localization fallback?

Any insights or suggestions from the community would be greatly appreciated!

Thanks in advance.