Process QuickLookUIService problem macOS High Sierra 10.13.6 Rhino 5.5.3

I’m having big memory consumption problems that lead Rhino to slow down until the OS window appears, the system has run out of memory (I have 32GB). Since my workflow had become “impossible” I did some research and that’s what I discovered. 1) The problem is the “QuickLookUIService” process (seen from activity monitoring) which (in this case) takes care of displaying the previews of the .stl files that I use for 3D printing by exporting the .3dm files. You can easily reproduce the problem by combining a Finder window with the Activity monitoring window. Selecting a .stl file from the Finder and pressing the space bar, you will see the memory used by the QuickLookUIService process on Activity Monitor increase. For me it is sufficient to view a few large files to finish the Memory. 2) the “temporary” solution for me is to close the QuickLookUIService process from activity monitoring when this indicates too high a value (I notice it because Rhino slows down). I found a solution on the net that could “solve” the problem and for this I need your help.This is a terminal command that “should” close the QuickLookUIService process after a certain time automatically.

function stahp () {dangerous script deleted}

$ stahp QuickLookUIService 30

I would have 2 requests, 1) check if the command works without “side effects” 2) check if the memory problem of the QuickLookUIService process also occurs with OS Mojave. Thanks for your help.

update: I was wondering if this process could also affect the “freezing” of Rhino (1-5 seconds) when macOS automatically saves large files and updates the preview in the Finder.

QuickLookUIService is an Apple utility and not something we provide. Apple can display previews of a number of file types, including OBJ and STL. We only provide a utility to preview 3DM files. You should report this problem to Apple here: You’ll likely need to submit a sample file that shows this problem.

Thanks Marlin, I will certainly send the report. The most important thing for me is to solve the problem and continue to use Rhino efficiently. Is it possible to check if the terminal command solves the problem and if this problem also occurs with macOS Mojave? (in this case I can think of an upgrade from High Sierra). Thank you.


I removed the script contents you posted above. It displays incorrectly in Discourse and will do bad things if someone else runs it. The original script text that was in your post is also wrong and should not be run.

I will not recommend running any script that kills Apple processes, and instead strongly recommend that you do not use that script.

As far as testing on Mojave, we can do this, but we will need a sample file for testing and a description of the behavior to be looking for.

@marlin I see. To test with Mojave, simply export any .3dm file in .stl from Rhino and reproduce what you see in the video that I have attached. If the file has a few hundred mb in size, it will make the test faster to perform.