When you create one of the reports grouped by payee, Quicken displays a Choose Payee button that you can click to select different payees to display in the report. Clicking this button opens the Payee tab of the Customize dialog which, by default, displays the payees used in the transactions for the last three years. If the payee you want isn't in the list, at the top of the Customize dialog, in the Date range field, select a date range that covers more than three years. Then try searching the list in the Payee tab again.
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Others have reported that there also appears to be a limit to the total number of items that can appear in the payee dropdown list and after that it drops random payees.