ARM64 on Windows: BadImageFormatException when loading SharpSvn.dll from .NET Framework 4.7.2 application — ARM64 assets only ship under net6.0, no net46/net48 for ARM64

[UtkarshBandekar]

Summary

On a Windows ARM64 machine, an application targeting .NET Framework 4.7.2 (net472) fails to load SharpSvn.dll with:

Could not load file or assembly 'SharpSvn, Version=1.14005.366.0, Culture=neutral, PublicKeyToken=d729672594885a28' or one of its dependencies.
An attempt was made to load a program with an incorrect format. (BadImageFormatException)

The host process is ARM64, and SharpSvn.dll is also ARM64 (PE Machine: 0xAA64). However, because the ARM64 RID in the NuGet package only provides lib/net6.0 assets (no net46/net48), the net472 CLR cannot load the ARM64 .NET 6 mixed‑mode C++/CLI assembly in‑proc, leading to BadImageFormatException.

x86/x64 work fine using runtimes/win-x86|win-x64/lib/net46, but ARM64 consistently fails for net472.

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Environment

• Application TargetFramework: net472
• Host OS: Windows 11 ARM64
  • OS: Microsoft Windows 10.0.26200 | OSArch: Arm64
  • Process: 64-bit | ProcArch: Arm64
  • Host EXE machine: ARM64
• SharpSvn NuGet: SharpSvn 1.14005.366
  • Runtimes present:
    • runtimes\win-x86\lib\net46 ✅
    • runtimes\win-x64\lib\net46 ✅
    • runtimes\win-arm64\lib\net6.0 ✅
    • Missing: runtimes\win-arm64\lib\net46 / net48 ❌

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What we deployed

• x86: from runtimes\win-x86\lib\net46 → works
• x64: from runtimes\win-x64\lib\net46 → works
• ARM64: from runtimes\win-arm64\lib\net6.0 → fails with BadImageFormatException

ARM64 file list (examples):

Ijwhost.dll
SharpSvn.dll
SharpSvn.xml
SharpPlink-*.svnExe
SharpSvn-DB44-20-*.svnDll

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Logs

OS: Microsoft Windows 10.0.26200  | OSArch: Arm64
Process: 64-bit | ProcArch: Arm64
Host EXE machine: ARM64
SharpSvn.dll Machine: 0xAA64
Unhandled exception reading assembly name from '...\arm64\SharpSvn.dll':
Could not load file or assembly 'SharpSvn, Version=1.14005.366.0...'
An attempt was made to load a program with an incorrect format.

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Expected behavior

• Either:
  1. Publish ARM64 assets for .NET Framework (net46/net48) alongside x86/x64, so net472 hosts can load SharpSvn in‑proc on ARM64; or
  2. Document that ARM64 is only supported for .NET 6+, and provide guidance for out‑of‑proc usage from .NET Framework hosts.

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Actual behavior

• ARM64 hosts running net472 cannot load SharpSvn.dll from win-arm64\lib\net6.0; CLR throws BadImageFormatException.

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Repro steps

1. Create a simple net472 app on Windows ARM64.
2. Reference SharpSvn 1.14005.366.
3. At runtime, load files from:
   • runtimes\win-x64\lib\net46 → works
   • runtimes\win-arm64\lib\net6.0 → fails with BadImageFormatException.

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Analysis

• SharpSvn embeds native Subversion/APR/OpenSSL payloads and uses C++/CLI IJW with Ijwhost.dll.
• NuGet selects RID + TFM assets; ARM64 only has net6.0, not net46/net48.
• A net472 CLR cannot load a mixed-mode .NET 6 assembly.

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What would help

• Add ARM64 assets for .NET Framework (net46/net48).
• Or document ARM64 as .NET 6-only and provide an official workaround pattern.

[UtkarshBandekar]

@rhuijben : Are there any plan to add support for ARM64 for .Net Framework 472

[rhuijben]

I am not sure if the compiler support for .Net/Cli is already in place to support this scenario. Last time I checked it wasn't.

I don't have the necessary hardware to check this myself. The build it's at GitHub is the only Windows environment with Arm64 cpu that I have access too.