GPi Case: Freezes when browsing Samba share

[Twoflower]

I'm having a weird problem. It's a freshly installed recalbox for GPi Case, on a Pi Zero-W. I have Wifi set up and working and the menu is playing music and everything. I can browse around and run through menus and there's no problems at all.

But when I use my windows PC to browse the \recalboxgpi\shares folder, Recalbox freezes. The music halts, the screen freezes, the entire unit becomes unresponsive. Flicking the power switch to OFF does not shut down and the only way to shut it down is to pull out the batteries or pull the Pi from its slot.

Any idea what could be going on? I know this is vague but it's all I have to go on...