HMaster will exit when starting with stale data in cached locations such as -ROOT- or .META.

later edit: I've mixed up two issues here. The main problem is that a client (that could be HMaster) will read stale data from ROOT or .META. and not deal correctly with the raised exceptions.

I've noticed this when the IP on my machine changed (it's even easier to detect when LZO doesn't work)

Master loads .META. successfully and then starts assigning regions.
However LZO doesn't work so HRegionServer can't open the regions.
A client attempts to get data from a table so it reads the location from .META. but goes to a totally different server (the old value in .META.)

This could happen without the LZO story too.