NuGet packages show "source not available" and aren't loading properly (with loading indicators stuck), follow this targeted troubleshooting guide

 1. Fix Package Sources Configuration

Check NuGet sources:

• bash

  dotnet nuget list source

  Ensure your primary source (e.g., nuget.org) is ENABLED and reachable.

• Re-add nuget.org:

  bash

  dotnet nuget remove source nuget.org
  dotnet nuget add source https://api.nuget.org/v3/index.json -n nuget.org

2. Clear NuGet Cache & Temp Files

bash

dotnet nuget locals all --clear
rm -rf /tmp/NuGetScratch/  # Linux/macOS
del %TEMP%\NuGetScratch\*  # Windows

3. Update NuGet Credentials (Private Feeds)

For Azure DevOps or private feeds:

bash

# Re-authenticate feed
dotnet nuget update source <SourceName> --username <User> --password <PAT> --store-password-in-clear-text

• Use --store-password-in-clear-text only for testing

4. Enable Detailed Logging

bash

# Restore with full diagnostics
dotnet restore --verbosity diag > restore.log 2>&1

Key things to check in logs:

• Source <name> is not available errors

• HTTP 401/403 authentication failures

• SSL/TLS handshake errors

5. Fix Project-Specific Issues

• Ensure SDK version compatibility in global.json:

  json

  {
    "sdk": { "version": "8.0.400" }
  }

• Disable parallel restores:

  bash

  dotnet restore --disable-parallel

6. Network & Security Workarounds

• Bypass SSL validation (temporarily!):

  bash

  export DOTNET_NUGET_HTTP_PROVIDER_ENV_SSL_VERIFY=false # Linux/macOS
  setx DOTNET_NUGET_HTTP_PROVIDER_ENV_SSL_VERIFY "false" # Windows

• Use HTTP instead of HTTPS (if blocked):

  bash

  dotnet nuget update source nuget.org --source https://www.nuget.org/api/v2

7. Visual Studio-Specific Fixes

1. Go to Tools > Options > NuGet Package Manager > General

2. Uncheck:

   • "Allow NuGet to download missing packages"

   • "Automatically check for missing packages during build"

3. Click "Clear All NuGet Cache(s)"

4. Restart VS as Administrator

---

Package Source Availability Test

Verify source accessibility with this C# code:

csharp

using var httpClient = new HttpClient();
var response = await httpClient.GetAsync("https://api.nuget.org/v3/index.json");
Console.WriteLine($"Status: {response.StatusCode}");
Console.WriteLine(await response.Content.ReadAsStringAsync());

Expected output: Status: 200 with JSON data.

---

Common Solutions Matrix

Symptom	Likely Fix	Command/Step
"Source not available"	Source misconfiguration	dotnet nuget update source
Packages stuck loading	Corrupted temp files	Clear /tmp/NuGetScratch
HTTPS errors	SSL bypass or HTTP fallback	export DOTNET_NUGET_HTTP_PROVIDER_ENV_SSL_VERIFY=false
Private feed issues	Re-authenticate with PAT	dotnet nuget update source --username ...
VS-specific hangs	Disable auto-restore & clear VS caches	VS Options > NuGet > Clear Caches

Final Checks

1. Test with new project:

   bash

   dotnet new console -n TestNuget
   cd TestNuget
   dotnet add package Newtonsoft.Json

2. Check corporate proxies:

   • Configure proxy settings via:

     bash

     dotnet nuget config set http_proxy http://proxyserver:port

If issues persist:

1. Share restore.log (last 20 lines)

2. Output of:

   bash

   dotnet --info
   dotnet nuget list source
   ping api.nuget.org