ChatGPT outputting gibberish how to fix

Why is ChatGPT suddenly generating gibberish?

When ChatGPT outputs unreadable text—such as random characters, repeated words, programming syntax symbols, or pure "word salad"—the issue usually stems from one of three areas: local browser translation conflicts, a corrupted conversation context window, or backend tokenization bugs on OpenAI's servers.

Because Large Language Models (LLMs) generate text token-by-token based on probability, a single corrupted token in a long chat history can derail the entire generation chain, causing subsequent outputs to degrade into gibberish. Follow these troubleshooting steps to identify the root cause and restore normal responses.

1. Disable browser translation and writing extensions

Automatic translation tools and overlay browser extensions are the most common causes of localized output corruption. Extensions like Google Translate, DeepL, or Grammarly attempt to parse and modify the webpage's DOM elements as ChatGPT streams text live, scrambling the rendering engine's output.

1. Look at your browser’s address bar for any active translation icons.
2. Disable automatic translation for chatgpt.com by selecting Never translate this site.
3. Turn off any active grammar checkers, ad-blockers, or accessibility overlay extensions.
4. Open an Incognito or Private window, log into ChatGPT, and prompt the model again to see if the issue persists.

2. Start a fresh conversation thread

If a conversation history gets corrupted, ChatGPT will continue to output gibberish in that specific thread. The model references previous responses to generate new ones; once a formatting or encoding error enters the chat log, the system's token prediction pattern becomes unstable.

1. Click New Chat in the top left corner of the sidebar to clear the active memory cache.
2. Submit a simple, direct prompt in English (e.g., "Please write a one-sentence summary of what a cat is").
3. If the output in the new thread is clean, avoid returning to the corrupted thread, as its context window is permanently poisoned.

3. Clear browser site data and cookies

Corrupted local storage files can prevent the web application from processing the API stream correctly, resulting in broken formatting or missing letters.

1. Click the lock icon next to the URL in your browser's address bar.
2. Select Site settings or Cookies and site data.
3. Click Clear data or Manage cookies and site data and delete all stored entries for chatgpt.com and auth0.openai.com.
4. Restart your browser entirely, log back in, and try again.

4. Check for backend model delivery issues

Sometimes, major backend model updates or infrastructure incidents cause temporary token generation anomalies across the entire platform. During these incidents, the model may loop indefinitely or spit out nonsensical text to all users.

1. Navigate to the official status tracker at status.openai.com.
2. Look for active incidents targeting the API, ChatGPT, or Model Delivery components.
3. If a "Degraded Performance" incident is noted, you must wait for OpenAI engineers to deploy a server-side hotfix.

5. Adjust API generation parameters (Developers)

If you are experiencing gibberish outputs when using the OpenAI API or the developer Playground, your generation parameters are likely set outside the model's stable threshold.

• Lower the Temperature: If your temperature parameter is set above 1.0, the model selects highly improbable tokens, quickly leading to random text. Reduce your temperature to a value between 0.2 and 0.7.
• Verify Top P: Keep top_p at its default value (1.0) or slightly lower (0.9). Avoid modifying both temperature and top_p simultaneously, as this compounding effect can break coherent outputs.
• Check Max Tokens: Ensure your token limit is not truncating JSON structures or system instructions mid-sentence, which can leave the parsing client unable to render the remaining text.

When to escalate

If you have tested the model on a completely different device (such as the official ChatGPT mobile app on cellular data) and still receive gibberish responses on fresh threads, the issue is on OpenAI's side. Click the Help bubble in the bottom right corner of the ChatGPT platform to submit a bug report directly to support with a screenshot of the corrupted generation.