Learn how to disable the ‘Last Played’ feature at the top of the window in the Battle.net Launcher.
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Open the Battle.net Launcher and log in with your account credentials.
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Under App > Advanced Features, ensure that the ‘Show Last Played bar’ is unchecked.
Hit DONE to close the Settings window.
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You should no longer see the Last Played bar at the top of your Battle.net Launcher.