I'm transferring my wp setup from one host to another. I've exported the wp_popularpostsdatacache file from the old, and imported it to the new. When I look in the settings, I can see posts under each time frame. However, when I switch to all-time and save, they disappear from there. No setting, however, makes anything show in the widget. Still just "no data".
Also, it won't hold onto any setting and keeps resetting to 7 days.