Vercel / Deployment

Vercel Build Succeeds Locally But ModuleNotFoundError on Deploy — Case Sensitivity Issue

Next.js app builds successfully on developer's machine (Windows/macOS) but fails on Vercel deploy with case-sensitivity module not found errors. File paths look correct but Vercel's Linux filesystem is case-sensitive. Includes evidence for Vercel troubleshooting demand.

Source-backed Last updated June 2, 2026 4 sources Needs local verification

Category: Deployment
Error signature: ModuleNotFoundError: Module not found: Can't resolve '@/components/forms/RegisterForm' | Build failed because of webpack errors
Quick fix: Check the build output, project root, and deployment platform configuration before redeploying.
Updated: June 2, 2026
Verification status: Source-backed
Evidence: 4 public source URLs

Before you change production

This page includes public source URLs in the imported troubleshooting record. Compare those references with your version and environment before applying changes.

Reproduce the smallest failing action and save non-secret logs before changing configuration.
Check versions for Vercel, related SDKs, package managers, CI runners, and hosting providers.
Change one setting or dependency at a time, then rerun the same failing command or request.
Avoid destructive commands, credential rotation, billing changes, or security relaxations without a rollback plan.

What this error means

ModuleNotFoundError: Module not found: Can't resolve '@/components/forms/RegisterForm' | Build failed because of webpack errors is a Vercel failure pattern reported for developers trying to next.js app builds successfully on developer's machine (windows/macos) but fails on vercel deploy with case-sensitivity module not found errors. file paths look correct but vercel's linux filesystem is case-sensitive.. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

GitHub Next.js issue #69390 and Vercel Community forums show this is a frequent pain point. The issue: Windows is case-insensitive for filenames, so 'RegisterForm.tsx' imported as 'registerForm' works locally. On Vercel's Linux build environment, this is a hard failure. Additional complexity when using tsconfig path aliases (@/lib/utils style) combined with gitignore issues or symlinked directories. Multiple devs confirm this is the #1 reason local-to-deploy build fails. High commercial value: blocks deployed apps, especially startups on free tier. Category: Deployment.

Common causes

GitHub Next.js issue #69390 and Vercel Community forums show this is a frequent pain point. The issue: Windows is case-insensitive for filenames, so 'RegisterForm.tsx' imported as 'registerForm' works locally. On Vercel's Linux build environment, this is a hard failure. Additional complexity when using tsconfig path aliases (@/lib/utils style) combined with gitignore issues or symlinked directories. Multiple devs confirm this is the #1 reason local-to-deploy build fails. High commercial value: blocks deployed apps, especially startups on free tier. Category: Deployment.

Quick fixes

Confirm the exact error signature matches ModuleNotFoundError: Module not found: Can't resolve '@/components/forms/RegisterForm' | Build failed because of webpack errors.
Check the Vercel account, local tool state, and provider configuration involved in the failing workflow.
Check the build output, project root, and deployment platform configuration before redeploying.

Platform/tool-specific checks

Verify the command, editor, extension, or API client that produced the error.
Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
Avoid deleting credentials, local model data, or project settings until the failing scope is clear.

Step-by-step troubleshooting

Capture the exact error message and the command, editor action, or request that triggered it.
Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
Review the source evidence below and compare it with your environment.
Apply one change at a time and rerun the smallest failing action.
Keep the working fix documented for the team or deployment environment.

How to prevent it

Keep provider/tool configuration documented.
Record non-secret diagnostics such as tool version, provider name, model name, and command path.
Add a lightweight check before CI or production workflows depend on the tool.

Diagnostic flow for this page

Match ModuleNotFoundError: Module not found: Can't resolve '@/components/forms/RegisterForm' | Build failed because of webpack errors exactly before applying the quick fix.
Compare the failing environment with Vercel versions, account scope, provider settings, and deployment context.
Check the listed common causes in order, starting with the cause that best matches your logs.
Use the evidence status below to decide whether to confirm against public sources or official documentation.
Apply one reversible change, rerun the smallest failing action, and keep rollback notes.

FAQ

What does ModuleNotFoundError: Module not found: Can't resolve '@/components/forms/RegisterForm' | Build failed because of webpack errors mean in Vercel?

ModuleNotFoundError: Module not found: Can't resolve '@/components/forms/RegisterForm' | Build failed because of webpack errors indicates the workflow described by "Vercel Build Succeeds Locally But ModuleNotFoundError on Deploy — Case Sensitivity Issue" failed in a Deployment context. Start by confirming the exact signature and the component that emitted it.

What should I check first for ModuleNotFoundError: Module not found: Can't resolve '@/components/forms/RegisterForm' | Build failed because of webpack errors?

Check whether this cause matches your environment: GitHub Next.js issue #69390 and Vercel Community forums show this is a frequent pain point. The issue: Windows is case-insensitive for filenames, so 'RegisterForm.tsx' imported as 'registerForm' works locally. On Vercel's Linux build environment, this is a hard failure. Additional complexity when using tsconfig path aliases (@/lib/utils style) combined with gitignore issues or symlinked directories. Multiple devs confirm this is the #1 reason local-to-deploy build fails. High commercial value: blocks deployed apps, especially startups on free tier. Category: Deployment.

Is the ModuleNotFoundError: Module not found: Can't resolve '@/components/forms/RegisterForm' | Build failed because of webpack errors guidance source-backed?

The "Vercel Build Succeeds Locally But ModuleNotFoundError on Deploy — Case Sensitivity Issue" page is labeled source-backed. It has 4 public source URLs from github.com, community.vercel.com, stackoverflow.com, so use that evidence status when deciding how much additional verification you need.

When should I avoid the quick fix for ModuleNotFoundError: Module not found: Can't resolve '@/components/forms/RegisterForm' | Build failed because of webpack errors?

For "Vercel Build Succeeds Locally But ModuleNotFoundError on Deploy — Case Sensitivity Issue", avoid applying "Check the build output, project root, and deployment platform configuration before redeploying." when the error text differs, the affected version or provider is different, or the change would touch credentials, billing, DNS, production deploy settings, or irreversible data.

What should I collect before debugging ModuleNotFoundError: Module not found: Can't resolve '@/components/forms/RegisterForm' | Build failed because of webpack errors?

For "Vercel Build Succeeds Locally But ModuleNotFoundError on Deploy — Case Sensitivity Issue", collect the failing Vercel command or request, non-secret configuration, versions, timestamps, request IDs when available, and the smallest reproduction that still triggers the signature.