Sanity Studio login screen source context error on dev and production

The "Could not find source context" error on the Sanity Studio login screen is typically a dependency or build issue. Based on the GitHub discussion, here are the most common solutions:

Quick Fixes

1. Clean install your dependencies (most common fix):

rm -rf node_modules
rm package-lock.json  # or yarn.lock / pnpm-lock.yaml
npm install

This resolves most cases where the error appears during development or build. Something often gets out of sync during upgrades, especially when migrating between major versions.

2. Pin your Sanity package versions: Remove carets from your package.json to ensure exact version matching:

{
  "dependencies": {
    "sanity": "3.x.x",  // instead of "^3.x.x"
    "@sanity/vision": "3.x.x"
  }
}

3. Update @sanity/vision: If you're using the Vision plugin, make sure it's on the latest version that matches your Studio version. Version mismatches here can cause context errors.

What's Happening

This error occurs when a component tries to use Sanity's internal React context (like useClient, useDataset, or useSource hooks) but can't find the context provider. This usually means:

• Mismatched package versions between sanity core and plugins
• Duplicate React instances in your node_modules
• Corrupted dependency tree from a partial upgrade

The error shows up at login because that's when Studio components first try to access the Sanity client configuration through React context.

If You're Migrating from v2 to v3

Make sure all your @sanity/* packages are on v3 versions. Mixed v2/v3 packages will definitely cause this error. Check your package.json for any stragglers.

After cleaning dependencies, restart your dev server completely - sometimes the build cache needs clearing too. If you're still stuck after trying these steps, sharing your package.json dependencies would help diagnose further!