What is __MACOSX folder?
What are these __MACOSX folders I keep seeing in zip files made by people on OSX? Some take as much as 30% of the file.
What program are producing these __MACOSX folder and how can mac users avoid this mistake?
Apple provides built-in capability to ZIP files in OS X 10.3 and higher, and these files are the result of Apple storing Resource Forks safe manner. You would never see these files running OS X 10.3 or higher, but since Windows and other operating systems do not understand this special form of Resource Forks they will appear as you see them.
Here's a link that explains it pretty well. I suppose it is a bit late to help Yada, but for posterity.
Explanation of resource fork at Wikipedia
The rest is my opinion:
@nickf: Never seeing these files is not a FEATURE of those OS X versions it is a FLAW.
People produce data, wrap it up, store it on different mediums and so on. They need to know what is needed or what is not needed. Hiding it keeps them in the dark.
The age old bad idea of hiding things from users:
A programmer, concerned with expediency of accomplishing their own work, abuses something in the domain of the end user, to make it easy for themselves.
In this case they stored meta data in the user's data space, they then hid it from the user. They missed the big picture: The user won't become aware of the hidden details. When the user packages their data and ships it somewhere unanticipated by the programmer, missing parts won't get shipped or unknown parts will arrive which neither the user nor the recipient can explain.
Hiding things from the user is bad.
It assumes the user is stupid, when more accurately it is the programmer being stupid, or lazy.
To be clear, this bad habit is not confined to MAC. It is everywhere. It's a consequence of programmers falling in love with their own schemes and vendors prioritizing their own goals ahead of the needs of the end user.
In brief.
__MACOSX:
weird smelling programmer droppings emerging from under the rug where they were swept.
Programmers and vendors: Please keep things in the open. When you hide them, you make yourself stupid and the user uninformed.
To answer your final question:
how can mac users avoid this mistake?
macOS users can install a 3rd-party archiving utility like Keka, then tell it to not use Resource Forks, then set it as the default compressor.
How to do this with Keka
Tell Keka to not use Resource Forks
- Open Keka without a file (From Launchpad, Spotlight, etc.)
- Press ⌘ Cmd+, to open Preferences
- Select the Compression tab
- Check "Exclude Mac resource forks (eg: .DS_Store)"
Make Keka the default compressor
- In the same Keka Preferences window
- Select the General tab
- Click "Set Keka as default compressor/uncompressor" [sic]
What is __MACOSX?
This is a question that comes up a lot, particularly from Windows users. So what the devil is the folder called __MACOSX and what can or should I do with it?
The technical term for what is contained within this curious folder is a resource fork.
__MACOSX, as you may have gathered, will only be created on a Mac. If you’re creating files on Windows, you won’t ever (unintentionally) create these or see them.
However, a common place windows users do see these is in ZIP files that they download or files that they share with Mac users.
Outside of a Mac, they are useless. Depending on who you ask, you may get told that they’re useless fluff wherever they are – a debate that I’m sure will continue to rage on. The point being they do actually have an intended purpose in the OS X operating system.
So, why do Mac Users keep sending them to me if they’re useless?
The answer to this one is that Mac users simply don’t see these folders. Take the ZIP file that you’re looking at and have a look on a Mac a hey presto, just like magic, they’re invisible. And they aren’t the usual type of hidden folder. They’re really hidden! Hence why Mac users won’t remove them from the archive before they distribute.
Can I Delete The __MACOSX folder?
On Windows, absolutely – it’s no good to you at all. Just useless tat taking space up. On Mac, you can’t see it anyway.
The main complaint is that these files can, on occasion, take up massive amounts of space. Usually, they are KB’s so apart from cluttering up your file system and MFT the space they take up isn’t usually of a concern.
Reference: What is __MACOSX?