I have the same issue and found this service note that explains how to change the coin-cell battery inside. See: http://cp.literature.agilent.com/litweb/pdf/U1602A-02.pdf -- note that this URL may change once Agilent T&M moves to the Keysight domain -- but hopefully Agilent will put in redirects in the future...
This condition may also impact some other meter functions (my speculation). For example, I'm not able to restore factory default settings -- so not sure if that's related to any memory settings -- or it could just be a bug where some parameters aren't being reset for some reason.
This condition may also impact some other meter functions (my speculation). For example, I'm not able to restore factory default settings -- so not sure if that's related to any memory settings -- or it could just be a bug where some parameters aren't being reset for some reason.