[Public] Local Debugging of iOS Apps with 3rd-Party Libraries Doesn't Work on Windows

Developers using .NET MAUI to build cross-platform applications often run into limitations when trying to debug iOS applications from a Windows machine. This issue is especially evident when third-party native libraries such as IronOCR are involved.

One common error that arises when using IronOCR is:

Failed to locate 'libtesseract.5'...
Access to the path ... is denied.

Apple’s iOS Development Restrictions

Apple has a tightly controlled development ecosystem that enforces the following:

All iOS applications must be signed using a valid Apple Developer certificate.
Native libraries must be compiled for ARM64 and integrated using Apple toolchains.
iOS apps must follow strict sandboxing and file system rules, which limit access to certain paths during execution.

Because Apple's development tools (e.g., Xcode, codesign, lipo) only run on macOS, Windows machines are inherently limited in what they can do for iOS builds.

What Happens When Debugging iOS on Windows

When you attempt to debug a .NET MAUI iOS app on a Windows machine with a connected iPhone:

The app may launch on the device.
However, native libraries like Tesseract (used internally by IronOCR) may fail to deploy or load, resulting in runtime errors.

These issues typically occur because:

The library is missing or not correctly packaged.
The iOS app cannot access required file paths due to sandboxing.
Native code is not correctly signed or compiled.

Why It Works on Windows for Android/Windows Targets

On Android or Windows platforms:

Native libraries can be included and loaded without special tooling.
There are no signing requirements similar to Apple's.
Tesseract and other native code work as expected under IronOCR.

This is why the same codebase runs smoothly on Android or Windows but fails when targeting iOS from a Windows development machine.

How to Properly Build iOS Apps with Native Libraries

To successfully develop and debug iOS apps that depend on native libraries like IronOCR, follow these best practices:

1. Use a Mac

Develop directly on macOS or use Visual Studio’s Pair to Mac feature.
This allows you to offload builds to a Mac while coding on Windows.

2. Don’t Manually Copy Native Libraries

Let IronOCR manage library deployment.
Avoid manually altering paths or copying files unless you fully understand iOS's deployment model.

3. Test on Real Devices via macOS

Use real iPhones or iOS simulators from a Mac for accurate testing.