When using RemoteTech devices for remote control, it no longer recognizes MechJeb as a valid control. After valid communication with a RemoteTech ComSat - it used to allow you to choose "MechJeb" as the control - but it no longer switches to that - just stays at a red "Local Control" indicating there is nothing to control the vessel.

Sounds like a problem with RemoteTech needing to update to recognize MechJeb 2, not MJ's problem.

I find it amusing that this gets reported just after RemoteTech updates to a version that's supposed to support MechJeb 2.

What version of RemoteTech are you using? The old one is known to be incompatible; the new one should work fine:

Added MechJeb 2.x compatability. Speaks for itself. From 0.5.0.0 onward, RemoteTech is compatible with MechJeb 2.x. I've scrapped MechJeb 1.x compatability though.

(http://forum.kerbalspaceprogram.com/showthread.php/16347-PLUGIN-PARTS-0-19-1-RemoteTech-Relay-Network-%E2%80%93-V-0-5-0-0?p=302974&viewfull=1#post302974)

As noted above, this sounds like a RemoteTech problem, not a MechJeb one. I'm closing this until someone reports a problem with MechJeb 2 and RemoteTech 0.5+.