Hi Greg,
It definitely looks like a malfunction of your electronics. I would suggest to try and print over USB, rather than using the SD card slot. You can print over USB by changing this settings in Cura: Dropbox - File Deleted - Simplify your life If you then connect the printer via the USB cable, the “save to sd card” button in Cura will change to a “print over usb” button.
I don’t think the board or steppers are overheating, like numerous people are saying. If that would be the case you’d see shifted layers, rather than a complete crash of the printer. Of course it’s possible you’re experiencing multiple issues at the same time.
If you do decide to replace the electronics, I’ve got a spare electronics board which I’m willing to sell for a reasonable price 
This is the younger of my 2 printers. I bought it second hand, but it was only 2 months old and had less than 200 hours on it at the time. That was a few month ago. It has been working fine since then, and would theoretically still be in warranty but I don’t have a proof of purchase.
Raise a support ticket with Ultimaker. Which country are you based?
My original ultimaker2 board broke after a year and a half, the Ultimaker price for a new board was about 300€.
I got this Chinese one for around 100€, its been working fine for over a year now. I could have got 3 for the price of the Ultimaker one.
Best
Alexandre
Hi!
Maybe you can start swaping Z axis motor. If the problem persist the you should focus on the main board.
If you have 2 printers, swaping parts you will find were the problems come from.
Let’s see!
My first suggestion would be to make sure you download the most recent version of Cura and also install the most recent firmware. Once you have done that make sure to reset the machine back to factory default and see if that fixes your problem.
Try to level again the buildplate!! Maybe the nozzle does not have the appropriate distance from the buildplate.
Most likely the Z stepper is overheating so definitelyi reduce the Z current but dont’ print anything large until figuring this out. The next most likely thing is that your stepper is moving 2x as far as it should be - something wrong with the microstepping setting. I think there is a jumper on the board near the Z stepper driver that needs to be installed or removed. You can easily test this by moving the Z around - start at any height say 0mm from the glass then move to 10mm from the glass and I’m guessing it will be 20mm up instead of 10mm. Exactly.
There is a jumper somewhere. Contact support.
Your screen freezing is MUCH more troubling. Did you have USB connected when that happened? If so then disconnect. If not, send it back (the pcb). That should never ever happen.
Hey Gregh,
The problems I see listed in your post, to me, in my experience with troubleshooting hardware (having been on the programming side, as well as the hardware side) of designed systems: the described phenomenas in systems such as this, are as a result of hardware failure. This could be as you said a result of corrupted memory in my opinion, or an electrical component that has since become faulty on the board becoming sensitive after long hours of printing. My advice would be to look into a new board for your ultimaker such as the one in the following link:
Best of luck to you!
Thanks for this. Since reducing the current from 1300 to 1200 I did not see the original issue again on the Z axis. I did see similar overstepping on the Y though and I then reduced the current on the XY steppers similarly. That seems to be working, but there is heat-staining on the board that indicates that the stepper drivers have been overheating. I am now running a fan over the board while I print, but I now wonder if the overheating has caused other damage to the board becasue I am still seeing some freezing up and other quirks. UM GB is supporting me.
Thanks again for the suggestion.
Greg