Ok, this is probably a PEBKAC error, so please bear with me.
I went to the 3D printer class last night and got all excited and came home and got on Thingiverse to find something to print. Found a little keyfob thing, customized it with my name and downloaded it. When I go to my downloads to move it to my flash drive, I get an error that reads, “Invalid Public Key Security Object File This file is invalid for use as the following: Certificate Trust List.”
I don’t use any shareware and I’m running Windows 7 Home Premium so I may have some default security thingy I need to change?..maybe? I went online looking for information and got a stuff from Microsoft that is absolutely over my head. Anybody familiar with this?
In windows, the “STL” file extension could also be a certificate trust list. Is it possible you double clicked it? I wouldn’t think it’d try to verify the file before copying it.
When I double click the file to open it, it attempts to treat it as a certificate trust list (same wording you saw):
I didn’t get this dragging it between drives though, so the reason I asked if you double clicked it possibly. If you’re getting this somehow even properly dragging and dropping to copy, you could change the file extension to something else (“foo” for instance), copy it, and the rename it at the destination back to stl.
If I actually open up the file with MeshLab for instance, it’s clear it’s a valid 3D STL file:
Apologies to whoever created this STL file. It might have been @HankCowdog? I can’t remember right now, but please don’t send a cease and desist letter
Rather than double-click, I’ve just gotten in the habit of opening KISSSlicer first, then opening the STL file from with the program. IMHO, in a public environment where someone might be mucking about with the file extensions associations, this is the prudent thing to do with ALL files, not STLs.
The fact that Windows associates the .stl extension with Certified Trust Lists is unfortunate, because the warning message that shows up is more frightening than the usual “I don’t know how to open this file, please select from this list of programs” dialog.
