So, if I understand correctly, if I am printing with ABS and have the fan layer control speed on the cooling tab on the left set to Layer 1 Speed 0 to indicate NO fan at all for any layer in the entire print, the override is still going to turn on the fan when it thinks it is needed even though I s...

You may need to update the printer's firmware in order for the machine to know it's able to travel that far. I'm not sure where the documentation for this process is stored anymore as PrintrBot no longer is in business. Hopefully another user here has done such an upgrade and may be able to help.

Can you tell me what the purpose would be for your processes to each have different post processing scripts? I consider myself a power user. I wouldn't expect the software to know how to correctly handle three or more sets of terminal commands that it's being asked to run. I'm actually impressed it ...

If slic3r is working fine but you feel compelled to use Simplify3D, why not compare the infill settings for both softwares? Perhaps the infill extrusion amount is less in S3D or the print speed is too high in S3D?

I remember reading previously that smoothie had problems with densely packed movement commands. Do you have firmware updates available? There seem to be a high number of retractions on your first layer. Have you tried changing your advanced retraction settings to see if that makes a difference?

I'm on Yosemite and the upper infill label is updating when I input new values in the infill tab.

In which Mac OS version are you seeing this issue?

Here's the factory file that produced the gcode in my previous post. Slicing the other part of this assembly (a very similar part) in 4.0.1 produced very good print with no extruder skipping and zero stringing. PhotoLightTop.factory Disabling Retract During Wipe Movement resolved the mismatched ret...

+1 I'm also running OSX High Sierra (10.13.6) and ended up uninstalled S3D. S3D is just flat-out terrible on this version of OSX. Super slow and crashtastic. I've been running S3D with High Sierra since beta and haven't seen issues like you guys have been describing. Have you emailed support about ...

Try turning the external fill pattern to rectilinear. Concentric pattern is very specific toolpathing which won't work well as a bridge.

I'd start by comparing the starting script in the G-Code of each program. If there are obviously different commands being sent to start the print, I'd suggest trying the commands from the software that's working correctly as a replacement for the commands used by the software that's not working. If ...