Did you mostly use regular batteries, or recharable batteries? If rechargable what type?
All Duracell coppertop
rechargeable battery , Nicad
When low battery shut down, take battery out measured about 1.1 Volt
Most of the time the battery bar show about 1/2 full.
Most of the freeze occur at battery low.
When battery low, some song cannot select. or keep playing the same song regardless of which song you pick.
Most of the time fixed by power down. a few time need to take battery out.
Needed 2 format in about a year.