Thought I'd add to the suggestions and solutions on this thread by sharing my very recent experience. My MZ-RH1 is about 6 months old and used very rarely. With the ‘Low battery’ display flashing, I tried to recharge from the mains unit. Nothing - the unit kept going in to 'Data Save', "I'm switching off now" mode. Instead, I plugged the unit into my PC and got the ‘Charge’ message up. Immediately unplugged the unit from the PC and plugged back into the mains unit, and got the ‘Charging - mins left’ display. Possibly, it's some kind of firmware recalibration process that's occurring here but, hey, what I know about electronics appears to be on par with Sony Support.