Uploading Excel Files to Custom GPT

I have noticed when I create custom GPTs I have issues with it understanding uploaded files (in this case a spreadsheet). But if I upload the same file to regular Chat GPT, it works fine. How can I handle this so my custom GPT can behave the same way? thank you!

Are you uploading the spreadsheet as a Knowledge file or in a user message?

Good point - I need the user to upload the file and that is where the issue is occurring

Hi, how did you solve it? I have the same problem, my custom gpt does not read the file but the standar gpt read it. Thanks