Uploaded Files Visible in Chat but Not Accessible to Custom GPTs (and Attachment Quota Still Gets Consumed)

ChatGPT
1

Has anyone else experienced this recently?

I’m seeing what appears to be a bug involving file uploads and Custom GPTs.

What Happens

I upload one or more .mdx files.

The files appear correctly attached in the conversation.

I then ask the GPT to review or analyze the files.

Instead of processing them, the GPT responds as if no files were uploaded and asks me to send them again.

Example:

“For me to review your .mdx files, please send them here in the chat…”

The strange part is that the files are already visible in the conversation UI.

Additional Problem

After retrying the upload multiple times, attachment quota appears to be consumed even though:

  • The files were never processed.

  • The GPT never gained access to them.

  • The requested task was never executed.

Eventually I receive a message indicating that I have exhausted my attachment allowance.

Intermittent Error

In some conversations I also receive:

{
  "type": "image_generation_user_error",
  "code": "invalid_value",
  "message": "The model 'gpt-image-2' does not exist."
}

This is especially confusing because:

  • No image generation was requested.

  • The task was purely documentation review.

  • The uploaded files were MDX files.

Environment

  • ChatGPT Web

  • Google Chrome

  • Multiple Custom GPTs

  • Multiple retries

  • MDX documentation files

Expected Behavior

  • Uploaded files should be available to the GPT after upload completes.

  • Attachment quota should not be consumed when uploads fail.

  • Text-only workflows should not trigger image-related errors.

Actual Behavior

  • Files appear attached but are inaccessible to the GPT.

  • GPT asks for files that are already attached.

  • Attachment quota continues decreasing after retries.

  • Some conversations fail with a gpt-image-2 error.

Has anyone else encountered this behavior?

If so, have you found a workaround or received feedback from OpenAI support?

2

Update: Possible Root Cause Identified (.mdx Extension)

I performed additional testing and found a potentially important clue.

The issue appears to be related specifically to the .mdx file extension.

Failing Files

configuration.mdx
getting-started.mdx
index.mdx
installation.mdx
internationalization.mdx

Observed behavior:

  • Upload appears successful.

  • Files are visible in the conversation.

  • GPT cannot access the file contents.

  • GPT sometimes asks me to upload the files again.

  • Attachment quota may still be consumed.

Working Files

I renamed the exact same files from .mdx to .md:

configuration.md
getting-started.md
index.md
installation.md
internationalization.md

With no other changes, the GPT was immediately able to access and process the files correctly.

Expected Behavior

If .mdx files are not supported, the platform should reject them during upload and display a clear validation message.

Actual Behavior

The upload appears to succeed, the files remain visible in the UI, but the model cannot access their contents. This makes the failure difficult to diagnose and may lead users to repeatedly retry uploads, consuming attachment quota unnecessarily.

4

Thanks for the update @sylviohmartins.

Your testing is helpful here. .mdx files are supported and should be readable, so renaming them to .md shouldn't be necessary for the GPT to access the contents.

There was also a partial outage yesterday that affected some file-related workflows, which may explain why uploads appeared attached but weren't accessible to the GPT.

Are you still seeing the same behavior today with .mdx files, or has it improved since the outage was resolved? Also curious whether the gpt-image-2 error is still appearing.

-Mark G.