Jul 19, 2025

How to use zed with .NET (powered by omnisharp)

Why Zed

Recently I have been using my old laptop to code .NET & Astro.js for a project, but I have been frustrated by the fact that my laptop is not powerful enough to handle the load that made it freeze frequently due to OOM errors because of vscode. Tried to add more swap memory, it works and never faced OOM anymore but it burdens the CPU.

Did I tried Neovim? Yes, I tried Neovim, but it didn’t suit well me and it’s hard to set up. So, why Zed?

it’s fast
easy to use
feels like home (keymap vscode-ish)
support C# development (with some juggling)

Make Zed works well with .NET

Zed supports C# via its c# extension, but as I write this blog, it needs some configuration and unfortunately it is not well documented. So, here is step by step how I configured zed to work with .NET, but before we continue, I use linux mint here, so for other OS please adjust the steps by yourself:

Install OmniSharp by yourself from here, then make OmniSharp executable by running

chmod +x /path/to/OmniSharp

Install the extension
Add following configuration into settings.json

"lsp": {
  "omnisharp": {
    "binary": {
      "path": "/path/to/OmniSharp",
      "arguments": ["-lsp"]
    }
  }
}

Run dotnet --info and see where it is installed, in my case it is here

/home/linuxbrew/.linuxbrew/Cellar/dotnet/9.0.6/libexec/sdk

Find your libhostfxr.so is located, since my dotnet is located under /home/linuxbrew/.linuxbrew then I ran find /home/linuxbrew/.linuxbrew -name libhostfxr.so and make sure that you have the libhostfxr.so installed.
Now that you found libhostfxr.so, add this into you bashrc or any other shell configuration file:

export DOTNET_ROOT=/home/linuxbrew/.linuxbrew/Cellar/dotnet/9.0.6/libexec #
export PATH=$DOTNET_ROOT:$PATH

And finally, restart zed and enjoy!

Errors that might occur

Here are some errors that I encountered when setting up my zed

1. libhostfxr.so could not be found

The required library libhostfxr.so could not be found.
If this is a self-contained application, that library should exist in [/<omnisharp path>]

It happened because DOTNET_ROOT in your shell configuration file might be incorrect.

2. Failed to spawn command

Language server omnisharp:

failed to spawn command. path: "<OmniSharp path>", working directory: "<workdir>", args: ["optional", "additional", "args", "-lsp"]
-- stderr--

Your lsp.omnisharp.binary.path in settings.json might be incorrect, make sure you typed full path and remember that path is case sensitive.

3. Enumeration already finished.

System.InvalidOperationException: Enumeration already finished.
   at System.SZGenericArrayEnumerator`1.get_Current()
   at McMaster.Extensions.CommandLineUtils.CommandLineProcessor.CommandArgumentEnumerator.get_Current()
   at McMaster.Extensions.CommandLineUtils.CommandLineProcessor.CommandArgumentEnumerator.MoveNext()
   at McMaster.Extensions.CommandLineUtils.CommandLineProcessor.ProcessCommandOrParameter(CommandOrParameterArgument arg)
   at McMaster.Extensions.CommandLineUtils.CommandLineProcessor.ProcessNext()
   at McMaster.Extensions.CommandLineUtils.CommandLineProcessor.Process()
   at McMaster.Extensions.CommandLineUtils.CommandLineApplication.Parse(String[] args)
   at McMaster.Extensions.CommandLineUtils.CommandLineApplication.ExecuteAsync(String[] args, CancellationToken cancellationToken)
   at McMaster.Extensions.CommandLineUtils.CommandLineApplication.Execute(String[] args)
   at OmniSharp.CommandLineApplication.Execute(String[] args) in /home/vsts/work/1/s/src/OmniSharp.Host/CommandLineApplication.cs:line 65
   at OmniSharp.Stdio.Driver.Program.<>c__DisplayClass0_0.<Main>b__0() in /home/vsts/work/1/s/src/OmniSharp.Stdio.Driver/Program.cs:line 84
   at OmniSharp.HostHelpers.Start(Func`1 action) in /home/vsts/work/1/s/src/OmniSharp.Host/HostHelpers.cs:line 30

your args must be ["-lsp"] only, even though in zed docs it should be ["optional", "additional", "args", "-lsp"]

Still facing a problem? please hit me up through my linkedin, will be gladly to help you out.