What OpenAI documents
OpenAI's migration guide says "Migration turns your GPT's instructions into a skill and brings over its knowledge files and connected apps", and tells you to check that the migrated files work as expected, because transfer and retrieval may differ (Moving your custom GPT workflows to plugins). That is about moving the files into a plugin. It does not describe downloading them to your computer. The retirement FAQ and the sharing page are about dates and about who can use or migrate a GPT (Custom GPT retirement and migration FAQ; Sharing and publishing GPTs), and the excerpts we saw mention no download either. help.openai.com blocks automated reading, so we could read those two only through search excerpts; open the editor's Configure tab yourself to see whether your version offers a download.
What people report
- 24 October 2024, "How to backup or save Custom GPT": a user asks whether anything holds a GPT's data apart from the uploaded files and the instructions box. The one reply: keep your own copy of any files or prompts you use to build it (How to backup or save Custom GPT (October 24, 2024)).
- 22 January to 4 May 2025, "Files in custom GPT knowledge base disappeared": nine people say files they uploaded to their GPTs vanished, one up to 18 of them. One writes: "In some GPTs I don't document the files I uploaded, so the frustration is even bigger" (Files in custom GPT knowledge base disappeared (January 22, 2025)).
- 20 March 2025, "My custom GPT knowledge files have disappeared": the poster says restoring a previous version from the GPT's Version History brought the files back, but cannot bring back files that were not in the GPT at that point (My custom GPT knowledge files have disappeared (March 20, 2025)).
- 12 June 2026: a GPT owner writes that people with chat-only access can open and copy the knowledge files in the file panel of a chat. On 2 October OpenAI Support answered that "The GPT sharing guide distinguishes Can chat from Can view settings, but doesn't clarify this file-panel behavior" (Chat-only users can open/copy Custom GPT Knowledge files in the file panel (June 12, 2026)).
What to do today
- List what is there. Open the GPT's Configure tab and write down the names and the number of files under Knowledge.
- Find your originals. Search your computer, your email attachments and your cloud drive for each file name. A file you made for the GPT is often still in the folder you made it in.
- If a file is missing, look at the version history, if your editor has one. The 20 March 2025 report says an older version still listed its files. Restoring an older version is likely to replace the current setup, so copy your current instructions and action schemas first.
- Open a chat with the GPT and check the file panel. If the files open there, save or copy them straight away. This is the June 2026 report above, and it may not work for you.
- Put what you have in one backup. Skillcase keeps each file as it is in the backup's knowledge folder and in the skill's references folder, so the files travel with the instructions.
If the originals are gone
We found no documented way to get them back. Rebuild them from where they came from: the web pages, spreadsheets or notes you turned into files. If you ask the GPT to print a file back, treat the answer as a reconstruction rather than a copy: it can be shortened, reworded or wrong, so compare it with what you remember.
Files in a GPT you did not make belong to its creator. Ask the creator for a copy. Your own chats with that GPT are yours and are in your ChatGPT data export; see save your custom GPT chats.
Gemini Gems are different
Google does give you a download for a Gem's files. Its steps: open the Gem, click Edit, and "If the Gem has files under 'Knowledge', download your files. For each file, click the file to open it and at the top, click Download" (About the transition from Gems to skills). More in Export a Gemini Gem.
Pack your GPT before December 11
Paste your GPT's setup, add its knowledge files and your ChatGPT export, and download a backup you can open anywhere, a skill for Claude, Gemini and ChatGPT, and your chats as Markdown. Free, in your browser, and nothing is uploaded.
Questions
Can I download the knowledge files from my custom GPT?
OpenAI's help pages describe no download button for them, and we found none described. Look for the files you uploaded, and check the GPT's version history and the file panel in a chat, which users report helping some people.
My GPT's knowledge files disappeared. Can I get them back?
People have reported this since January 2025. One poster said restoring an older version from the GPT's Version History brought their files back. OpenAI has not documented a fix, so keep your own copies.
Do knowledge files move when I migrate a GPT to a plugin?
OpenAI says migration brings over the knowledge files, and that transfer and retrieval may differ, so check them afterwards. The original GPT becomes read-only.
Can I download the files of a GPT someone else made?
They belong to its creator, and only the creator or a workspace admin can migrate it. Ask the creator for a copy. Your own chats with the GPT are in your ChatGPT data export.
Sources: OpenAI: Moving your custom GPT workflows to plugins; OpenAI Help: Custom GPT retirement and migration FAQ; OpenAI Help: Sharing and publishing GPTs; OpenAI Developer Community: How to backup or save Custom GPT (October 24, 2024); OpenAI Developer Community: Files in custom GPT knowledge base disappeared (January 22, 2025); OpenAI Developer Community: My custom GPT knowledge files have disappeared (March 20, 2025); OpenAI Developer Community: Chat-only users can open/copy Custom GPT Knowledge files in the file panel (June 12, 2026); Google: About the transition from Gems to skills. Last checked: October 28, 2026. Skillcase is an independent tool by Peak Apps Studio and is not affiliated with OpenAI, Anthropic, Google or Ollama.