@viczena I was pretty sure we already had the discussion about not being rude. You really need to take it down a notch here. There is really no justification for your aggressive behaviour here. You're trying to push blame onto @foosel when it was you who made the decision to install an RC when you didn't know what it was.
BTW: You can disable plugins in config.yaml, which you would have known, had you read the docs. 
@viczena You could provide some valuable insight into this if we knew what type/version of browser you're using. In this way, someone could confirm your assertion that the 1.3.10rc1 Setup Wizard is having problems.
There's also a chance that it has something to do with your settings in your browser, with your local network and a variety of other things.
Good job Foosel 
Mmu2 is working thanks a lot!
It's a release candidate IE: BETA SOFTWARE to be TESTED by people willing to and ABLE to HANDLE the issues.
Loaded for a quick look and immediately had issues with Enclosure Plugin. Buttons didn't react when clicked. I cleared the cache, tried several different browsers but needed to get the system back up and printing. I switched back to the stable version with no issues. I will set up a separate raspberry pi and configure it to see if I can provide more details.
When buttons don't react, the first thing I do is to jump into the Developer's console to see if the JavaScript is suddenly unhappy. JavaScript has a way of just throwing up its hands and not continuing if it sees errors.
what does "Print with OctoPrint" in Cura mean?
Like USB printing - like sending g-code via wifi all the time ? It sounds like it could be more fragile
When you press “print with octoprint”, the gcode file is first sent to octoprint in its entirety (as if you had saved and uploaded it manually), and then printed by OctoPrint.
Once the file is sent to OctoPrint, Cura can be closed or restarted without affecting the print. During printing, you can view the progress from inside Cura (or in the OctoPrint web interface, if you prefer)
there is checkbox in Cura "Store G-codeon the printer sd card" and note "transfering files to the printer sd card takes very long. using this option is not recommended"
So they arent the same? Or someone mistaken then?
There are two SD cards; the one in your raspberry pi and the one in your printer. Uploading to the sdcard in your printer takes a LONG time, because it needs to go over the same connection a print goes. If you leave that option unselected, the gcode goes to the raspberry pi sdcard, which should be fairly quick.
But this is all fairly off-topic, so if you have furthet questions or suggestions it may be better to open a new thread.
I'm also seeing the GCODE viewer not working anymore. Unfortunately haven't had any time to do any troubleshooting or submit a bug report. Looks like it's already been picked up with https://github.com/foosel/OctoPrint/issues/2873 so I'll see how it goes with RC2.
Side note: when most applications ask for "submit anonymous info" I'm always a little bit hesitant, but when OctoPrint requested? Couldn't find the "oh hell yeah" button so had to settle for just saying yes. 
@JohnnyGTO Please open a ticket and we'll figure out if that's an OctoPrint issue or a plugin issue (sometimes plugins use things that aren't officially documented and hence not guaranteed to be kept backwards compatible).