I have clocks set to under 60 and yet it keeps overunning. Can't seem to localize the cause
PlayIt Live will always fill the hour from the playout pattern if the clocks are underrunning. I would recommend you add a fixed time marker at the start of the hour to reduce the amount of overrun.
Thanks, Jason, One thing I didn't know. Always good to keep learning
The underrun message isn't an error as such, it just shows that you need more material to have a complete hour.
The concept of PlayIt Live is that you will get the playlist songs played out in order (with suitable cross fades) and the playlist (like most radio) is based around a "Clock Hour" which, say, starts at 09:00 and ends at 09:59:59 (so a second before 10am).
It's a bit different to "AutoDJ" in something like Mixxx which just wants to play songs until it runs out.
To resolve it, as no doubt you have now found out, ad some more music (or other items such as break notes) to fill the hour up.