version: "1.0.0" name: maui-doctor description: Diagnoses and fixes .NET MAUI development environment issues. Validates .NET SDK, workloads, Java JDK, Android SDK, Xcode, and Windows SDK. All version requirements discovered dynamically from NuGet WorkloadDependencies.json - never hardcoded. Use when: setting up MAUI development, build errors mentioning SDK/workload/JDK/Android, "Android SDK not found", "Java version" errors, "Xcode not found", environment verification after updates, or any MAUI toolchain issues. Works on macOS, Windows, and Linux.

.NET MAUI Doctor

Validate and fix .NET MAUI development environments.

Key Principle

All version requirements discovered dynamically from NuGet APIs. Never hardcode versions. See references/workload-dependencies-discovery.md.

Behavior

• Run through ALL tasks autonomously
• Re-validate after each fix
• Iterate until complete or no further actions possible

Platform Support

Workflow

Task 1: Detect Environment

# macOS
sw_vers && uname -m
 
# Windows
systeminfo | findstr /B /C:"OS Name" /C:"OS Version"
 
# Linux
cat /etc/os-release && uname -m

Task 2: Check .NET SDK

dotnet --info
curl -s "https://raw.githubusercontent.com/dotnet/core/refs/heads/main/release-notes/releases-index.json"

Compare installed vs latest-sdk where support-phase is "active".

Task 3: Check MAUI Workloads

Linux: Use maui-android NOT maui (meta-workload includes iOS deps).

Task 4: Discover Requirements from NuGet

See references/workload-dependencies-discovery.md for complete process.

Query NuGet for workload manifest → extract WorkloadDependencies.json → get:

• jdk.version range and jdk.recommendedVersion
• androidsdk.packages, buildToolsVersion, apiLevel
• xcode.version range

Task 5: Validate Java JDK

Only Microsoft OpenJDK supported. See references/microsoft-openjdk.md for paths and detection.

Verify java -version output contains "Microsoft".

⚠️ TEMPORARY WORKAROUND: The jdk.recommendedVersion from WorkloadDependencies.json currently returns 17, but recommend JDK 21 instead. This will be fixed in a future Android workload update. Rule: If WorkloadDependencies suggests ≤21, recommend 21. If it suggests >21, use that value.

Task 6: Validate Android SDK

Check packages from androidsdk.packages, buildToolsVersion, apiLevel (Task 4).

See references/installation-commands.md for detection commands.

Task 7: Validate Xcode (macOS Only)

xcodebuild -version

Compare against xcode.version range from Task 4.

Task 8: Validate Windows SDK (Windows Only)

Get-ItemProperty "HKLM:\SOFTWARE\Microsoft\Windows Kits\Installed Roots"

Quick Diagnosis (Before Reinstalling)

⏱️ 2-minute check that can save hours. Many "missing tool" errors are actually path/environment issues.

Diagnostic Steps:

1. Is it actually missing? Check with direct path: ls -d /Applications/Xcode*.app, ls /Library/Java/JavaVirtualMachines/
2. Is it a shell issue? Open NEW terminal and retry
3. Is it an env var issue? Check echo $ANDROID_HOME, echo $JAVA_HOME - often these don't need to be set

Only reinstall if the tool is genuinely missing from disk.

Task 9: Remediation

See references/installation-commands.md for all commands.

Key rules:

• Workloads: Always use --version flag. Never use workload update or workload repair.
• JDK: Only install Microsoft OpenJDK.
• Android SDK: Use android sdk install (if tool available) or sdkmanager.

Task 10: Re-validate

After each fix, re-run validation. Iterate until all pass.

Optional Tools (Third-Party)

Highly recommended to simplify and make validation and remediation more reliable / consistent.

Ask before installing: "This is a third-party tool (not Microsoft). Install it?"

Important Notes

• Linux workloads: Use maui-android + android (NOT maui)
• JDK: Only Microsoft OpenJDK. Look for "Microsoft" in java -version.
• JDK Version: ⚠️ Recommend JDK 21 (not 17) until WorkloadDependencies.json is updated.
• JAVA_HOME: Not required. Only problematic if set to non-Microsoft JDK.

Context-Specific Guidance

CI/CD Pipelines

For automated builds (Azure DevOps, GitHub Actions, etc.):

• Pin versions: Always use dotnet workload install --version X.Y.Z for reproducibility
• Use `--skip-manifest-update`: Prevents drift between pipeline runs
• Cache aggressively: NuGet packages, workloads, Android SDK (~90% hit rate saves 5-10 min)
• Accept licenses non-interactively: echo y | sdkmanager --licenses
• Avoid: dotnet workload update, dotnet workload repair (non-reproducible)

Expected build times:

Linux (Android-Only)

• Workloads: Use maui-android + android (NOT maui)
• KVM acceleration: Critical for emulator performance

``bash sudo apt install qemu-kvm && sudo usermod -aG kvm $USER # Log out/in for group change kvm-ok # Should say "can be used" ``

• Disk space: Expect ~8-10GB for SDK + emulator images
• Streamline .csproj: Remove unused TFMs

``xml <TargetFrameworks>net9.0-android</TargetFrameworks> ``

Productivity Tips

Shell aliases (~/.bashrc or ~/.zshrc):

alias maui-build='dotnet build -f net9.0-android'
alias maui-run='dotnet build -f net9.0-android -t:Run'

macOS parallel setup: Start iOS simulator download in Xcode while continuing with SDK/workload installation.

References

• references/workload-dependencies-discovery.md - NuGet API discovery process
• references/microsoft-openjdk.md - JDK paths, detection, installation
• references/installation-commands.md - All validation and install commands
• references/platform-requirements.md - Platform-specific details
• references/troubleshooting.md - Common issues and solutions