GPT to Plugin migration rejects knowledge files accepted by the GPT

ChatGPT Feature requests
1

I’m trying to migrate my custom GPTs to plugins, and the migration tool is asking me to replace knowledge files because they are “too large.” These same files were accepted by the GPT and are essential to its purpose. Each contains distinct source material. Replacing one with a smaller, different file means losing information and potentially reducing the quality of the assistant.

The error messages make this worse. The tool identifies one file as too large. After I replace it and try again, it identifies another. Why doesn’t it show all incompatible files and the applicable size limits upfront?

I have several specialized GPTs that I use regularly. I should not have to discard part of their knowledge to keep using them after a product migration I did not choose.

Please provide a way to migrate existing knowledge files in full, explain the different file limits, and show every incompatibility before asking users to change their GPTs. A migration that requires removing unique sources does not preserve the GPT we built.

2

I am having the same issue. I made a copy of my custom GPT and tried converting it to Plugins and it said the files were too big. What’s the point then? They should fix this issue because after December Custom GPTs are going away and I need to migrate my GPTs to Plugins before I lose access to them.

3

Thanks for confirming you’re seeing the same problem. I ran another test that may help narrow it down.

The GPT-to-plugin migration rejected my complete 1647 edition of William Lilly’s Christian Astrology as “too large.” I then created a private plugin from scratch and added that exact, unmodified PDF as a skill reference file. The plugin update succeeded, and the file appears in its published file list. It is 21.29 MB (20.3 MiB) and has 876 pages.

I have also seen the migration reject a file only slightly larger than 2 MB, while the same GPT contained other files larger than 10 MB. This makes the error difficult to interpret as a consistent per-file size limit.

I have confirmed that the manually created plugin accepts the Lilly file; I have not yet tested how reliably it retrieves passages from that PDF in conversation. Could OpenAI clarify what the migration tool is actually checking, why it rejects files that a plugin can accept, and why it reports incompatible files one at a time?