fatal: Unable to create '.git/index.lock'

All errors Free
Git

fatal: Unable to create '.git/index.lock'

Git could not create .git/index.lock because a lock file for the index already exists.

What it means

Git could not create .git/index.lock because a lock file for the index already exists.

Likely cause

Another Git process is running, or a previous command crashed and left a stale lock behind.

How to fix it

Wait for any running Git process to finish; if none is active, remove the stale lock with "rm -f .git/index.lock" and retry.

Other Git errors

fatal: not a git repository Git ran a command outside any repository, so it has no .git directory to work with. ! [rejected] ... (non-fast-forward) The push was rejected because the remote branch has commits your local branch does not, so it cannot be fast-forwarded. CONFLICT (content): Merge conflict in A merge, rebase, or cherry-pick could not automatically reconcile changes to the same lines of a file. Permission denied (publickey) The SSH server rejected the connection because no accepted public key was offered during authentication. fatal: The current branch has no upstream branch The current branch has no remote tracking branch, so Git does not know where to push or pull. fatal: refusing to merge unrelated histories Git refused to merge two branches that share no common commit ancestor. error: Your local changes would be overwritten by merge Git aborted the merge or checkout because it would discard uncommitted changes in your working tree. fatal: remote origin already exists A remote named "origin" is already configured, so adding another with the same name fails. error: src refspec main does not match any The branch you tried to push does not exist locally, so Git has no source ref to send. remote: Authentication failed / password removed The remote rejected your credentials, commonly because password authentication over HTTPS is no longer accepted. fatal: Need to specify how to reconcile divergent branches Git 2.27+ will not pull because your local and remote branches have diverged and no reconciliation strategy is configured. fatal: detected dubious ownership in repository Git refused to operate on the repository because its files are owned by a different user than the one running Git. error: pathspec did not match any file(s) Git could not find any file or branch matching the path or name you supplied. You are in 'detached HEAD' state HEAD points directly at a specific commit rather than a branch, so new commits are not attached to any branch. remote: error: File is too large (GH001) The remote rejected the push because a file exceeds the host's per-file size limit (GitHub caps files at 100 MB).

About Error Code Lookup

The Error Code Lookup is a searchable directory of more than 200 common error messages and codes across 12 categories: HTTP status codes, Windows error codes, browser and network errors, JavaScript, Python, PHP, Node.js and npm, Java, MySQL, Git, Linux shell errors and email/SMTP codes. Every entry is written in plain language for quick troubleshooting.

Each error is explained in three parts: what the message actually means, what usually causes it and concrete steps to fix it. That structure turns a cryptic string like ERR_CONNECTION_REFUSED or 0x80070005 into an actionable checklist instead of a guessing game.

You can filter the list by category, search by code, constant or message fragment, and copy any code with one click. Every error also has its own dedicated page with related errors from the same category, so you can bookmark or share a direct link to the exact fix.

How to use Error Code Lookup

  1. Type the error code or message into the search box — for example 404, ERR_NAME_NOT_RESOLVED or 0x80070005.
  2. Narrow the results with the category filter (HTTP, Windows, JavaScript, MySQL and so on) if the search returns too many entries.
  3. Open the matching entry to read what it means, its likely cause and how to fix it.
  4. Use the copy button to grab the exact code for a bug report or support ticket.
  5. Check the related errors section for other errors from the same category.

Frequently asked questions

It covers 12 categories: HTTP status codes, Windows system errors, browser and network errors, JavaScript, Python, PHP, Node.js and npm, Java, MySQL, Git, Linux shell errors and email/SMTP reply codes — more than 200 entries in total.

Search with fewer words. The shortest unique part works best: just the numeric code (“404”, “0x80070005”) or the constant name (“ERR_NAME_NOT_RESOLVED”) rather than the full sentence your system printed.

Yes. Each entry has a dedicated detail page explaining the meaning, likely cause and fix, plus related errors from the same category. You can bookmark it or send the link directly to a colleague or a support ticket.

The fixes describe the standard, widely accepted resolution for each error. Still, read the likely-cause section first — the same code can have several triggers, and matching the cause to your situation tells you which fix applies.

Yes, it is completely free. You can search, browse the category directory and open as many error detail pages as you need without an account.
Share this
Related Tools
Code Formatter Beautify HTML, CSS and JavaScript — re-indent and add line breaks to make messy or minified code readable. Free
Code Minifier Shrink HTML, CSS and JavaScript — strip comments and whitespace to make files smaller and load faster. Free
Array Formatter Expand inline arrays and objects onto clean indented lines, or collapse them back inline — for PHP, JavaScript, TypeScript, JSON, Python, Ruby and more. Free
Regex Tester Build, test and debug regular expressions live in your browser — instant match highlighting, capture groups, substitution preview, a plain-English explanation and ready-to-paste code for 15+ languages. Free
Cron Expression Builder Build a cron expression from a simple, visual form — set each field, see the live expression, human-readable schedule and next run times, then parse any expression back into the form. Free
JWT Decoder Decode a JWT header & payload (signature not verified). Free
Popular searches
error code lookup error message database what does this error mean windows error codes chrome error codes http error codes list fix error message error code meaning
Need help?
Found an issue with this tool? Let our team know.
Report an issue

Add this free tool to your own website — copy and paste the code below.