just upgraded one of my 15 RB2011 routers to v 6.39... totally crashed. Was not able log back into it without driving to the site. Upon re-accessing it everything in the programming was wiped back to default. Took multiple trys to get the IP address set to static, kept reverting to automatic. once I got it stay I was able to get it to downgrade to 6.37 bugfix. Never had this issue with a OS upgrade, whats up?

There is 6.39 related thread. Use it.