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Codex becomes extremely slow and causes severe UI lag when working with many files

OpenAI Developer Community March 13, 2026
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When using Codex to generate or modify code across a large number of files, the entire application becomes extremely slow and laggy. After Codex creates or edits many files within the same session, the UI responsiveness drops significantly. Simple actions such as scrolling, switching files, typing, or opening menus start to lag noticeably. In some cases, the editor becomes nearly unusable. This issue seems to worsen as the number of files involved in the task increases. Once Codex has interacted with a large set of files in the project, the performance degradation becomes persistent until the application is restarted. Expected behavior: Codex should be able to handle multi-file code generation or modification tasks without causing severe UI lag or degrading the overall responsiveness of the application. Actual behavior: The application becomes extremely slow after Codex processes many files. UI interactions become delayed, typing lags, and the overall experience becomes frustrating and inefficient for development. Steps to reproduce (example): 1. Open a medium-to-large project. 2. Use Codex to generate or modify code across many files. 3. Continue working in the same session for a while. 4. Observe that the editor gradually becomes very slow and unresponsive. Additional notes: Restarting the application temporarily resolves the issue, but the slowdown returns once Codex again processes a large number of files.

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