Hello Kiwikobi,
Welcome to the HP Forums!
I understand your Officejet 8600 won't align the printhead. I can relate to how frustrating this situation is. I am here to offer some suggestions to try and resolve this issue. Please follow these steps:
1) Make sure this printer is plugged into a direct wall, not a surge protector
2) Remove all of your ink cartridges from the printer and close the door
3) Remove the power cord from the back of the printer (Do no press the power button)
4 Wait 60 seconds or more, then plug the power cord back into the printer
5) Wait for the printer to turn on completely, then install the ink cartridges
6) Try to print an alignment page
If these steps don't resolve your issue, then please follow this entire HP document on An 'Alignment Unsuccessful' Error Message Displays on the All-in-One.
Please post your results, as I will be looking forward to hearing from you. :smileyhappy: