Why clicking Cancel on browser does not cancel print when SD card is used?

What is the problem?

I print using the SD card on my i3MK3S. When I clicked Cancel on my browser, the print process was stopped. However, unlike printing directly from Octoprint, it did not actually cancel the print because when I tried to print another file from the SD card, the nozzle would just start from the middle and printed mid-air. This has happened many times. How come?

What did you already try to solve it?

To prevent this from happening, I would need to go to the printer's LCD to choose Stop the print and Yes. Then, I could do the next print without issue.

Additional information about your setup

OctoPrint version, OctoPi version, printer, firmware, browser, operating system, ... as much data as possible

Mac OS 11.5.2
OctoPrint version 0.18.0
Prusa i3MK3S

I do believe the documentation even states that Octoprint cannot control the printer while it is printing from the SD card

1 Like

You may insert a gcode script in OctoPrint after cancelling a printjob to "reset" the printer.

OctoPrint should have sent a command to the printer that tells it to cancel the SD print. So this should not happen. Why it happens is impossible to say without you sharing the requested information.