Default App Ultimatums

[9valkyrie]

So, I went to double-click on my STL files after the recent 26.2 update and they open in Preview. So, I went in and changed the default app to my slicer. Now every time that I double-click on an STL file macOS claims that it's malware and won't open it. AFAIK STL files cannot contain malware. I can open 3MF files by double-clicking on them (they open in the slicer), but not STL. The slicer is signed and it passed Gatekeeper on every execution (no bypassing). I've tried a wider range of files and the story is the same: if you change the default app to anything besides Apple apps (Apple is the developer), it's deemed as malware and it won't open. You can change it back to the original Apple app, and it opens just fine, no problems at all. So, in my case I can set it back to Preview and it'll open just fine. Apple or nothing apparently. Anyone else have this problem? How do I fix this?

 

[Bigwaff]

I've tried a wider range of files and the story is the same: if you change the default app to anything besides Apple apps (Apple is the developer), it's deemed as malware and it won't open.

Can you list the "wider range of files" you tried and the applications you tried to assign to the files? This info would eliminate the hunt-n-peck someone would need go through to try it themselves. Let's zero in and replicate the exact behavior. Also, apologies, but I'm not familiar with an application called "my slicer" or "the slicer". What is that? Thanks.

 

[FreakinEurekan]

I'm not encountering this behavior after setting .STL files to open in BambuStudio slicer. No error messages such as you're reporting.

macOS v26.2, BambuStudio v2.5.0.66

Are you able to right-click on a file in Finder, then Open With > your slicer? Same issue or different?
Sounds like possibly a 3rd party security software could be involved - e.g. antivirus??

 

[9valkyrie]

Oh, sorry. It's OrcaSlicer. And I may have a clue as to why files are reporting as malware now. Some funny errors have come up which indicate that if a file is NOT created on this particular install of macOS and this particular MBA (hardware), it's untrusted (not necessarily malware, false positive). It doesn't even matter which file. One of the errors had to do with some sharing something or other, but basically it's saying that the file was from AirDrop and it cannot be opened because of that. I have files from a backup hard drive that are deemed as untrusted (there goes all that data). But if I actually create the file on this mac, it's seems to be trusted. It's apparently something new in this version. The previous version of macOS didn't complain too much. Sorry, for the confusion everyone. I'm confused too.

Edit: It could be missing metadata? macOS cannot find the metadata attached to the file? macOS has massive amounts of metadata for files.

 

[9valkyrie]

Are you able to right-click on a file in Finder, then Open With > your slicer? Same issue or different?

I can do Open With without issues.

 

[FreakinEurekan]

Very odd. I also tried setting the default for .STL to Anycubic PhotonWorkshop (the other slicer I use) and again, no issues. I've never used OrcaSlicer.

I've not seen any of the sort of errors you're referring to, from any files. I updated to 26.2 shortly after it was released, so around 6 weeks ago. I'd say it's some sort of software issue on your installation.

Try removing login items - if that doesn't sort it, boot into Safe Mode and see if it's working better there. If so, normal Apple menu > Restart (which takes you out of Safe Mode) might be all you need to do; if the issue comes back let us know. Probably some 3rd party app you have installed just not playing well with 26.2

 

[tonmischa]

My two cents: It is possible that the com.apple.quarantine Flag has been set on those files. (This could have been set by airdrop, copy on an older system, ...)

Try this terminal command
sudo xattr -r -d com.apple.quarantine <directorypath>
where directorypath is the folder which contains your files.

This will remove an existing quarantine flag and MIGHT solve your problem.