What causes "npm ERR! ERESOLVE unable to resolve dependency tree"?

Two packages require incompatible versions of the same peer dependency Installing a package that requires a different version of React than you have Using npm v7+ which enforces peer dependencies strictly (unlike npm v6) An outdated package that hasn't updated its peer dependency requirements

Error3 Fixes Available

npm ERR! ERESOLVE unable to resolve dependency tree

npm ERR! ERESOLVE unable to resolve dependency tree

What does this error mean?

npm can't install your packages because of conflicting peer dependency requirements. One package requires a version of a shared dependency that's incompatible with what another package requires.

Common Causes

Two packages require incompatible versions of the same peer dependency
Installing a package that requires a different version of React than you have
Using npm v7+ which enforces peer dependencies strictly (unlike npm v6)
An outdated package that hasn't updated its peer dependency requirements

How to Fix It (3 Solutions)

Use --legacy-peer-deps flag

This tells npm to use the old (npm v6) behavior and ignore peer dependency conflicts.

Code

npm install --legacy-peer-deps

# Or set it permanently for the project
npm config set legacy-peer-deps true

Use --force flag (more aggressive)

Forces npm to install even with conflicts. Use with caution.

Code

npm install --force

Upgrade the conflicting package

Check if there's a newer version of the package that supports your dependency versions.

Code

# Check what versions are available
npm info package-name versions

# Install a specific version
npm install package-name@latest

Related Errors

pip ERROR: ResolutionImpossible — dependency conflict

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Error: ENOENT — no such file or directory

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npm ERR! EACCES permission denied

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