Print stops: USB connection when program is in background

Hi everybody,

I have Prusa Mendel I2 which is connected through usb to my Macbook Air.
The only problem is, when I am printing and decide to do something else, for example use safari, the printer stops.

I send the printer signals through Pronterface and the USB needs to stay connected when I am printing.

It always worked in Mountain lion, but since Mavericks, the printer stops when I put Pronterface in the background.
It continues again when I go to mission control or if I click on Pronterface.

I would guess it de-activates the USB port or something.

I couldn't find any solutions on the internet, so I'm hoping somebody here could help me with it.

Kind regards,
Natascha

Edited 1 time(s). Last edit at 01/02/2014 04:57PM by Nsverhagen.

I don't have Mavericks (still 10.6.8 and glad) but I see people are having all kinds of USB issues on laptops since Mavericks. Some speculate that it's super picky about the amount of power a USB device is drawing, if this is the case then a fix would be to use a powered USB hub. However it sounds to me more like a glitch in the OS since it's working and then stops if you switch programs. Most people having these issues though report error messages telling them there is an issue with USB, you did not say you got any errors.

I wonder if there is something in Mavericks that is actually causing the program to pause. You could bring up the Activity monitor to see if that is so. Or you could try using Repetier Host instead (it's a much better program than Pronterface anyway).

Edited 1 time(s). Last edit at 01/02/2014 10:59PM by tmorris9.

I believe Mavericks has a power saving feature which suspends programs when they are in the background. I'm pretty sure there's a way to tell it not to do that for certain programs. Not owning a Mac myself, I don't know exactly how to do that.

i have a mac, and until i did a Google search i had no idea how to fix this issue. since i read the hack fix, I now find this feature of app nap annoying. here is the link to the article that fixes app nap feature when background apps are needed to run.


[lifehacker.com]

Ok. I have the issue for the new 10.9 also. The new function is call app nap. Go to the app>get info and disable the app nap. And it will be ok.

Thanks everybody, this solved it for me!