I was finally successful in using the Transactions > Corporate Acquisition feature of Quicken to adjust the fund information when Oakmark changed my share class in 2021. Quicken "Removed" all the share transactions prior to the change (one transaction) and then "Added" the adjusted share information (several dozen transactions). Unfortunately Quicken now no longer lets me select any Oakmark shares to Sell (I don’t want to sell right now--I am simply trying to be proactive in planning my mutual fund redemptions over the next few years). My general question at this point is: how do people deal with the issue of IRS filing requirements when the fund transaction history is inaccessible or incomplete or otherwise inaccurate?