All the changes I made in the slicer are stored in the 3MF file.

I have corrected my two 3MF files.

Unfortunately, I didn't notice that I had selected and uploaded the wrong files.

The two correct files are now online. One with and one without nozzle preheating.

Sorry!

I anticipated these questions. All the changes I made in the slicer are stored in the 3MF file. The modified GCode can be found in the "Printer Settings" tab in Prusa Slicer in the "Custom GCode" and "Start GCode" menu. Copy this section in "Start Gcode" using "CTRL + A" and "CTRL + C" and replace it with the existing Gcode in your slicer in the same place.

Just a reminder:

This code only works reliably if the print bed has been preheated and the nozzle is clean.

Didn't had a Look at Github!

Allow me one more Question:

Wanna try your GCODE, dled it, expected a TXT-File to paste in PrusaSlicer. Got a 3MF.

Just import?

Greetings and thanx,

Anyone else got this?

There are many posts here in the forum describing the same error.

There are also many cases on Gitub that match what you have written.

You can also report your case on GitHub. The more people report it, the faster something will likely be changed.

Until then, you can try my GCode.

If you want to have “peace” again and want to “turn it on and go” like before, do what I did, reinstall 6.2.6, and wait to see what Prusa fixes here.

since the Upgrade to 6.4.0, before every Print, a Nozzle-Cleaning will be done. Nothing new so far, before 6.4.0 this Cleaning was also performed.

But I guess, the detailed Procedure has changed. At the Moment, I print lots of PETG. 

Before cleaning, a Heat-Up and a Retract is performed (as I can read on the Printers Display), and in most of the Cases a little Bit of Filament is extruded

which keeps the Nozzle-Cleaning-Process from Success, because it "blocks". When i redo the Procedure, I manually clean the Nozzle with a Brush, and voila: The Print starts!

Anyone else got this?

Greetings,