Problem with the first few mm of every print…
Could anyone help with this problem please - as it's driving me mad.
I built the kit version of the MK3S and the first batch of prints were perfect. It was an absolute joy to use. Then for no specific reason this (see pic) started happening. The first 3-4mm one every print ramps from one side. After this 3-4mm it continues to print the rest of the file perfectly.
This happens with both files I make in Fusion360 and export to Prusa Slicer (2.2.0+) and files I've downloaded from various places. Also, files which previously printed without issue are exhibiting this problem.
I've tightened the belt on the X(?)/extruder axis - as recommended by someone on the Facebook group - but it hasn't solved the problem.
I'd really like to get this sorted as the printer has gone from almost continuous use to no use for about 6 weeks. 
RE: Problem with the first few mm of every print…
If you rotate the part 90 degrees, does the shift stay in the same position on the bed or rotate with the part? This may indicate insufficiently or improperly tightened belts, or bearing lubrication. Check your build instructions carefully and go over those steps.
and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan
RE: Problem with the first few mm of every print…
Or a slipping pulley on the X or Y axis, the ones fastened at the stepper motors.
The Filament Whisperer