I was traveling in November and December last year so didn't do much 3D printing.
When I got back and started 3D printing again in January I thought it was a good idea to upgrade Octoprint to the latest version (don't recall what I had before the upgrade). At the same time I upgraded Ultimaker Cura from 5.7 to 5.9.
My 3D printer is an Ultimaker 2+.
My usual workflow is to send my files to Octoprint which runs on a dedicated rPI. On the rPi which is where my 3D printer is - I usually set tool and bed temperature manually (because it happens in parallel)
I noticed a couple of weird things with the new Octoprint/Cura version.
From time to time - either my printer or rPI/Octorprint would crash. I can understand that if the power supply for my printer can't handle heating bed and tool at the same time that this could cause a problem. It's just that for the last couple of years this has never been a problem.
The other issue - and more frustrating is that if I upload a print to Octoprint and start it from Octoprint - the printer starts heating up the bed. (This is normal) Then it starts heating up the tool (normal as well) however - with the newest software version - once the bed temperature has reached it's level the printer starts printing no matter what the tool temperature is. And needless to say that if the tool temperature is too low nothing prints.
Anyon experienced similare issue?
What is most likely to be causing this? Which software should I try downgrading first ?
Hello @rssorensen !
If you need help then choose the correct sub-forum: Get Help.
Please try again there and give all requested information.
Here we only can guess.
not sure if this will help, but check there is M109 (wait for temperature) before the first gcode command that actually extrudes filament.
if all you have is the M104 to start heating, but continue without waiting, then what you have described is a quite likely outcome.
I moved you post to get help 
As @erffrfez already mentioned - there are two different heating gcodes. One lets the printer wait for the temperature and the other one just changes it on the fly.
The first one is usually used in your start gcode. It does exactly what you want: the printer halts and waits until the temperature of your hotend and hotbed (and maybe chamber - if you have one) are reached until it does anything else.
The second one is usually used in the mid of a printjob, for example when you have different temperatures at the first layer. You don't want the printer to stall for 30 seconds mid print until the new temperature is stabilized.
Just post your start gcode from cura here and I'm pretty sure we will find the issue there
I recently had a similar problem wherein both bed and tool temp was not reached before it started.
Rebooted in safe mode and problem went away so that confirmed it was one of my plugins that has suddenly borked. In my case I suspected the "Enclosure plugin" and disabled it in Plugin Manager. Rebooted, and its is working again.
Gool luck in your problem solving.