Thank you for reaching out to the Community with this question.
When you go across the top to tools > scheduled updates what does yours look like? Generally, to turn it off you'll want to un-checkmark all of the accounts. Once that's done you can hit ok and it should turn them all off so you aren't prompted for the scheduled update anymore. I'll leave a photo down below.
Please let me know if this helps resolve the issue for you.
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If you don’t mind, could you please provide a screenshot of the issue you described receiving where it says you must pick one day? If needed, please refer to this Community FAQ for instructions on how to attach a screenshot. Alternatively, you can also drag and drop screenshots to your response if you are not given the option to add attachments.