UM3: Rod Detached at Start of print

[donbon 0]

I placed the printhead back on the rod and snapped the rod back in place but I'm curious if there's something else I should so to make sure it doesn't happen again. Also I'd like to know how it happened in the first place: was there some routine maintenence that would have prevented this?

[Dustin 150]

You can find the maintenence schedule here: https://support.makerbot.com/s/article/1667337928504

But that actually isn't really covered..
It typically should not be possible to cause that without user error (pressure applied to the head while cleaning print cores or reinstalling bowden tubes) Though even then it generally should not happen..
Additionally failed prints which resulted in the print head crashing into the print can potentially cause this.

If you have unclipped the rod several times it could have worn the clips out.. 
Or one of the blocks might be cracked from age/heat.. 
Your local reseller has replacement sets.