Macbook Pro 13 (late 2013) - external disks unmount after sleep

I've seen many other similar posts - just adding mine to the pile - wondering if anyone has seen a fix or has a recommendation

Macbook Pro 13 inch (late 2013) the Thunderbolt and firewire drives unmount when Macbook pro sleeps. (NOTE firewire drive connected via Thunderbolt display - but same happens with TB drives when connected direct to MBP)

Not a showstopper - but frustrating - fix would be nice.

Thanks

PS I had a Macbook Air 2011, with no "unmount" problem when i upgraded to Mavericks.

PPS - Really enjoyed moving from MBA to MBP 13 - superior build quality, keyboard much better and display.... amazing. Weight difference neglible.