Hi guys,

When I download an offline installer for a Mac game using GOG Galaxy it work perfectly fine, no errors or anything, and it installs without warning.

But when I use the website to download the exact same offline installer I get this error when trying to open it:
"...file.pkg" can't be opened because apple cannot check it for malicious software.

Please note, I do know how to get around this error, but it is still weird and annoying and forces me to use GOG Galaxy (which have a lot of issues at the moment).

I hope this gets fixed, thanks for the efforts.

Coincidentally I used that exact offline installer yesterday, and it works without issues (downloaded from the website since I almost never use Galaxy). I heard something about that happening if you use Safari instead of Firefox/Chrome/etc., though I used Safari and it's fine.

Thanks for the reply,

The file was downloaded using Firefox, I tried Safari after your reply and still the same issue (image attached).
This error happens to all games downloaded via Browsers, I just used this file as example because it's small (20mb)

I'm using macOS Big Sur 11.5.2

Funny enough, when I download GOG Galaxy Installer (which is also a .pkg installer) from the website using any browser, I don't get this warning message.

I compared the files downloaded via browser vs. Galaxy, and the file contents are 100% identical, but Galaxy downloads files without any extended attributes, whereas a browser download adds some metadata. Namely download date/where from/last used, but also com.apple.quarantine, which I assume is causing your problem. I'd guess that's a Big Sur issue, which I'm not using. You can remove the quarantine attribute using the shell:

sudo xattr -r -d com.apple.quarantine /path/to/MyApp.app

Wow, thanks man!

That simple command really does fix the issue.

I just wonder why the GOG Galaxy installer file isn't affected like this.

Anyway, the fix is simple enough to not worry about it, thanks again!

As I mentioned, it doesn't add any metadata when downloading files. Looks like Firefox can be configured to not add the com.apple.quarantine attribute...do "show package contents" for Firefox, open Contents/info.plist, then change

<key>LSFileQuarantineEnabled</key>
<true/>

so it's <false/> instead.

It sounds like Apple's overzealous thing about installing things from outside the app store is getting the better of you. I'm pretty sure you can disable that if you want to though.

Errr, this and this contradict each other though. If you know how to disable that "error" (not so much an error as a deliberate restriction) then you're not being forced to use Galaxy.

I'm glad you got it working though, sounds like a problem of Apple's making (the metadata indicating it was downloaded from the internet is fine, the problem is Apple not trusting you to run anything downloaded off the internet). Galaxy didn't add any metadata so you were fine.

That's not what's happening at all. If iBeeze had not already changed the setting to allow non-app store apps, then Galaxy would not work, nor would any games from GOG. Installers downloaded from GOG are codesigned already (see attachment, nothing to do with the app store). So yes I'd consider that an error or at least Big Sur behaving differently compared to earlier versions of the OS for some reason, considering the absence or presence of the quarantine attribute makes no difference for me. If you don't know anything about macOS, please don't try to "help", thank you.

Thanks, but I may not have made myself clear in that sentence,

What I meant was, when I go to gog.com website and download the installer file of "GOG Galaxy for Mac" (galaxy_client_2.0.41.110.pkg) using Firefox, it does not display that warning when installing.

It's not a big deal, I was just curious about how "galaxy_client_2.0.41.110.pkg" installs without warning when downloaded using Firefox from gog.com, but when I download a game's ".pkg" file from the same website using the same browser they show the warning.

I checked using xattr and the galaxy_client.pkg even has the same "com.apple.quarantine" attribute that you mentioned, weird...

Oh, I see. Indeed that's a good question. Clearly there has to be some difference in the .pkg files but I have no idea what.

This is a public forum, and I merely offered speculation in response to the OP before continuing to read the thread and responding to the rest of the thread (merged as the last paragraph of my post). There's really no need to get territorial, I was just discussing the issue and not trying to steal your helping-thunder.
I doubt this is a bug and more of a deliberate change in behaviour Apple have implemented. You yourself said that the most likely reason it doesn't have an effect for you is that you're not running Big Sur, so it would appear that in Big Sur Apple have added a behaviour where it blocks the installation of a pkg downloaded in a browser. Your browser is already adding the quarantine attribute, it's just that your OS isn't paying attention to it.

Whoa, sounds like you don't know anything about this. Better not try and "help". ;P