Confirm before starting a print

What is the problem?

The features setting in Octoprint "Confirm before starting a print" does not wait or display a conformation message when I print directly from my slicer.

What did you already try to solve it?

I toggled the setting "Confirm before starting a print" and restarted Octoprint. I tried the latest version. It works if I manually drop the file on the browser window, but not if I print from the slicer.

Have you tried running in safe mode?


Did running in safe mode solve the problem?


Systeminfo Bundle

browser.user_agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.114 Safari/537.36
connectivity.connection_ok: true
connectivity.enabled: true true
connectivity.resolution_ok: true
env.hardware.cores: 4
env.hardware.freq: 1400
env.hardware.ram: 917016576
env.os.bits: 32 linux
env.os.platform: linux2
env.plugins.pi_support.model: Raspberry Pi 3 Model B Plus Rev 1.3
env.plugins.pi_support.octopi_version: 0.17.0
env.plugins.pi_support.throttle_state: 0x80000
env.python.pip: 19.3.1
env.python.version: 2.7.16
env.python.virtualenv: true
octoprint.safe_mode: false
octoprint.version: 1.6.1
printer.firmware: Marlin (May 31 2021 16:09:20)
systeminfo.generator: systemapi


I sent the test prints to replicate the problem from PrusaSlicer 2.3.0, but I also tried Cura with identical results.


Hello @adaycj !

If you want to confirm the print start within OctoPrint anyway, you may disable "Start printing after upload" in the PrusaSlicer upload popup window:


Side note:

You may cool your Pi a bit (more):

That's working as designed. Since it is your slicer acting as frontend to OctoPrint when you use it to send files over, OctoPrint cannot really control what to do before a print is started. Your slicer a) should give you the option to not even start printing an uploaded file immediately (which @Ewald_Ikemann pointed you to) and b) could additionally implement a confirmation dialog.

There's no way for OctoPrint however to force it to do all that.

I do not see a dialog like that when I print. I'll.spend some time today and try to find a setting to make it appear. What slicer and what version is the screen snippet from?

I'm not a programmer or software engineer so I don't know anything about what it can or can't do. All of the gcode goes thru Octopi and then over the USB to my printer when I print this way. Octoprint is my only window into what happens on my RPi. The feature says "confirm before starting ..." so I tried it. If it works as designed, fair enough. In my use case it does not work as the user expected. My expectations were wrong.

Octoprint has many features to control what happens when these job are sent. It even triggers Arc Welder to post process the gcode when I turn it on, but that does little good when the print job has already started seconds ago. If printing from a slicer to Octoprint circumvents all of them, I misunderstood.

If the setting doesn't work in my use case I can just save the gcode locally and drag and drop to the Octoprint screen in a browser. There is also a way to activate Arc Welder from the slicer so I may just do that for cases when I need it.

Thank you for the reply.

This is from PrusaSilcer-2.3.0

After slicing I click G:


And this window appears:


Thank you for that. After a fresh upload of PrusaSlicer I now have that dialogue. I have no idea how I lost it. It is also the solution to my problem. The "Confirm before starting a print" feature checkbox works only as nanny "are you sure?" after you click print in Octoprint.
The dialogue you suggested does what I need, to hold the uploaded print job so Octoprint's plugins can have its way with it. Perfect, and thank you.