reverting back to RH v1.0.6 seems to have resolved the communication timeout errors.
the large part that was giving me fits before has finished printing successfully, and running another larger part now with no problems yet.

uninstalled v1.6.0. restarted computer and re-installed v1.0.6 (the version I was using prior to the update).

fired up the printer, loaded up the piece that I thought was the problem before, and sliced... it is a large piece - fills the bed pretty well, but not real tall, and it is being printed at 100% infill. the main body is only 21 layers high at a 0.3mm layer height and as i type this it is at layer 16...

all failures before were before layer 10...

*hopeful*

Could simply be a bad cable..

Also a believe there is a box in setting that disables update checks thus no pop up.

the bad cable came tomy mind as well, but do you think I can find the spare cable I bought for the Rumba?? no...

if there is a checkbox to turn off updates I would love to know where it is hiding, cause I havent found one.

anyway, things worked pretty well for a while (a couple of weeks), the latest version of Slic3r bundled with it is nice too - has some new features that I am liking.

Now, for no apparent reason, it has started "crashing" - RH stops responding to commands & printer stops dead in the middle of a print.

at first I thought it might be the file I was trying to print - it failed 3 separate times on the same file...but others would print fine. chatted with knowack last night about it, he even offered to try printing the file I was having a problem with...

I turned on the log save function in RH so it would save a copy of the log as a txt file so I could review it after killing everything when this happens...

this morning, I fired everything up, started the bed heating - had not even loaded a file yet - and it quit responding again - bed was still heating but nothing working in RH... had to kill power to the printer, and shut down RH the hard way (task manager>end task)

the 12.18.15 RH crash 1 file is from that instance...note the last line - "communication timeout"

moved the USB cable to another port on the computer, rebooted everything, and tried again...

heat bed, so far so good...
load a file and slice - still working...
bed is ready, heat extruder - all is well so far...
start print - and it starts printing fine...
then suddenly it stops dead in it's tracks... print was about 2/3rds of the way done - printed a copy fine last night.

Well poo.... kill everything again, and go dig up the log (12.18.15 RH crash 2) - hmmm, "communication timeout" thing again.

so - anyone have any thoughts about this one?? I am at a loss as to why it would work fine for a couple of weeks and then suddenly start crashing left & right

FWIW - I have triple checked baud rate settings - all instances are the same - COM port, RH connection settings and firmware - all set to 115200 as this computer only goes to 128,000 in the COM port settings.

This is on a Windows 7 pro, 64 bit, dual core processor machine with 12gig RAM, the USB port is straight off the motherboard - no card, not a hub.
Printer is my #1 SD4 running on the Rumba board...
other than various slic3r settings changed, I have made no other changes to the setup since updating RH.