Aider error
Aider: Exception: Application is not running. Application.exit() failed
Exception: Application is not running. Application.exit() failed.Status: Fixed in releaseLast verified 1 documented fix2 sources
What it means
With --watch-files, the file-watcher thread crashed while trying to interrupt the input prompt. In issue #2716 the reporter traced it to TERM=dumb, for example when running aider inside an Emacs interface. The maintainer explained that watching for file changes needs to be able to interrupt the input prompt.
Causes
- Running --watch-files in a dumb terminal (TERM=dumb), where the prompt cannot be interrupted (issue #2716).
How to fix it
- Fix 1.
Upgrade to v0.71.0 or later. The v0.71.0 release notes say: "Turn off fancy input and watch files if terminal is dumb." The issue was marked fixed on Jan 10, 2025.
Terminalpython -m pip install --upgrade aider-chat
More Aider errors
All 17 Aider errorsThe LLM did not conform to the edit format.Status: WorkaroundSearchReplaceNoExactMatch: This SEARCH block failed to exactly match lines in {path}Status: WorkaroundModel gpt-3.5-turbo has hit a token limit!Status: WorkaroundModel foobar: Unknown context window size and costs, using sane defaults.Status: By designModel azure/gpt-4-turbo: Missing these environment variables:Status: By designaider: The term 'aider' is not recognized as a name of a cmdlet, function, script file, or executable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again.Status: Workaroundaider-chat 0.23.0 requires somepackage==X.Y.Z, but you have somepackage U.W.V which is incompatible.Status: WorkaroundThe API provider is not able to authenticate you. Check your API key.Status: By design
Related reading
- Aider vs Claude Code in 2026: Git-First Open Source vs Subagent RuntimeAider vs Claude Code: git-first, model-agnostic Aider against the Claude Code runtime of subagents and hooks. Compare architecture, cost, governance and fit.
- Aider vs Claude Code: Open Source vs Commercial AI Coding CLIAider is open source and works with any model. Claude Code is Anthropic's commercial agent. Here is how they compare for TypeScript.
FAQ
What does "Exception: Application is not running. Application.exit() failed" mean in Aider?
With --watch-files, the file-watcher thread crashed while trying to interrupt the input prompt. In issue #2716 the reporter traced it to TERM=dumb, for example when running aider inside an Emacs interface. The maintainer explained that watching for file changes needs to be able to interrupt the input prompt.
How do I fix "Exception: Application is not running. Application.exit() failed"?
Upgrade to v0.71.0 or later. The v0.71.0 release notes say: "Turn off fancy input and watch files if terminal is dumb." The issue was marked fixed on Jan 10, 2025.
Is this Aider error fixed?
Status: Fixed in release. A release fixed this. The affected versions note says where the fix landed. Affected versions: Reported on v0.70.0 and v0.70.1.dev; addressed in v0.71.0.
Sources
Last verified against 2 sources: official docs, maintainer replies and release notes.
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