Filament Mapping Screen is annoying
Is there anyway to avoid interacting with the "Filament Mapping" screen prior to every print? I really like the new MMU3 firmware, but I really hate this screen. I used the MMU2 for years and it had it quirks, but having to go across the other side of my house and press the knob for every print is ridiculous. 
RE: Filament Mapping Screen is annoying
I don't think I see that screen for every print.
The issue might be that the printer doesn't know what's loaded (as indicated by the "FIL" instead of the filament type, you can set that with the advanced preload) and/or that you didn't set a specific extruder in PrusaSlicer. But it's just a guess, mine is busy, so I cant test it right now.
RE: Filament Mapping Screen is annoying
It is true that if I go and preload all 5 lanes with filament, the prompt does not appear. Part of my frustration, is how did you know that. I haven't found any real documentation about how this tool is supposed to work and its apparent function is so for foreign to how I've ran my printers for years. There is an overview of the tools features for the XL, but it doesn't contain the particulars of how you must use it. Just so anyone reading this post knows, I really like the new MMU firmware and functionally, I'm just hoping someone can fully explain to the rest of us how to properly use it without breaking the remote printing functionality.
I really don't see the point of the tool on the MK4 / MMU3 combo, maybe it has more utility for the XL, I don't know. It seems sort of ridiculous that I have actually load filament in all 5 lanes before I can print without interacting with this screen. Yes 2 of the lanes on my MMU have short pieces of filament hanging out the back just to fool this tool. I don't get.
Maybe I just don't understand the real purpose of this FEATURE and eventually some real documentation will show up.
Thanks for your comments. I'm sure things will work themselves out.
RE: Filament Mapping Screen is annoying
I've tried this out in the mean time. On the printer, I always use the advanced preload when I'm loading a different type of filament. In PrusaSlicer on the top right, I've got the appropriate filament profiles selected as they are loaded into each slot and below that in the objects list, I'm selecting the extruder I want for each object (or alternatively, it will default to extruder 1). After clicking "upload and print" with these settings, the selection screen on the printer only appears if the filament types don't match (e.g. if you have selected extruder 1 with a PLA profile, but the MMU thinks something else is loaded).
It doesn't matter what's loaded in the slots that aren't used during the print and it's not a problem if they're empty. The MMU doesn't have a way to notice if you pull a loaded filament out, because the only filament sensor on it is the Finda on the selector. It just assumes that any filament you have loaded is in there and available until you load something else.
RE: Filament Mapping Screen is annoying
I only have an MK3SMMU3 which I dont use much these days so I could be wrong. But there should be two different printer settings in PrusaSlicer for your MMU printer: "MMU" and "MMU Single". If you use MMU Single then you will 100% get asked which of the five filaments is used for a print. If you use MMU (not single) then whatever filament you specify in the slicer is what is automatically used, no interaction needed, if left as "Default" then by default filament 1 is used.
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RE: Filament Mapping Screen is annoying
As @ventrue3000 noted, if you don't tell the printer what filament type you have loaded using the Load Filament Advanced screen then you'll get this screen on every print. Knowing that has pulled me back from the edge, but it would have been nice be able to read about how its works. I'll take all the help I can get thought.
After leaning about the load advanced function, I found that the printer will not tell you what filament types you have programmed in if opening the screen when no print is queued up. So the only way to know what Fil. types are programmed in is to put a conflicting filament type in you slicer and start the print.
I haven't tried single mode yet, because I use the MMU not only for color changes, but to have multiple filament types available to support differing print needs. Thanks for the heads up that I'm stuck with this screen even in single mode. There is a feature request in to provide a disable function for this tool.
With the MMU2, I was frequently guilty of trying to print with the wrong filament, and sometimes had to unjam the thing, but now this feature keeps me from printing at times when it just doesn't matter. I'm sure I figure it out eventually.
Thanks for you comments.