Yesterday I was trying to change a filament during a printing process, it was done at 86%, I paused a print, changed a filament and resumed a print but it started to print with a shift to the right, you can see it on the photo, I'm 100% sure I didn't touch a printer head nor printing bed so it is hardware/software issue. How to avoid it in a future? I wasted about 30 g of my filament.
It is a linear shift along a single axis, so it looks like a belt/pulley slipped.Try making sure that all of the pulley grub screws are tight, with an eye on the pulleys for the problem axis.
Watch this video if you need a reference: http://support.zortrax.com/hc/en-us/articles/201002262-XYZ-Axis-Maintenance
Let us know if that doesn't work.
I did what you suggested, thank you. It worked but now I have another issue, 2 hours ago printer has finished a job and printer head moved all the way to the left and when it reached the end X motor still was spinning and I heard grinding noise for a second. I have sent the same part to print and when it was done couple minutes ago and printer head moved all the way to the left X motor was continuing to move the head so it was grinding for like 3-4 seconds. What can it be and how to fix it?
Check your end stop to make sure it is functioning correctly.
I don't know "official" way, but this is what I would do for a quick check:
Note: if you're not careful you could cause it to crash. Try this at your own risk.
With the printer off, move the print head to front middle. Start up the printer, get your hand over the power switch and the other over the endstop switch (left side on either front or back of printer - not at home right now so I can't check). Have somebody start a print, and when it starts moving (returning home) click the endstop. If it changes direction the switch worked, if it keeps returning (leftwards) the switch has failed. Either way, immediately shut the printer off as the head will jam into the wall since it didn't home correctly.
Another way would be to find exposed wires to test for continuity, but I think that the switch is sealed so you'd have to get to the connection on the motherboard.