Q: Sending Mac JPEGs to a PC

When you say "send", are you emailing them or giving them a flash drive? If giving them a flash drive, how is it formatted and how did you copy the files to the drive?

These are files that are invisible on the mac but unfortunately visible on the pc side. It usually means that the original file had a resource fork.

How are these files being created?

It sounds like most of what you're describing are the AppleDouble files, which are created on DOS/Windows formatted drives by the Mac OS. A little history makes this easier to understand.

Windows is a single file system. Every file or folder is contained as a single entry on the drive. The Mac is a twin fork (file) system. They are the Data and Resource forks - also known as A and B trees.

The data fork is the main file. Such as the image of a JPEG. The resource fork is a separate, but linked file that can contain a bunch of different things related to the data file, but is mostly for the Type and Creator codes, and the image icon.

Since DOS is a single fork system, it's not possible for the Mac to write the file/folder data the way it normally would on a Mac formatted drive. So it creates a separate file to hold the resource data on a DOS/Windows formatted drive. That's what your PC users are seeing. Such as:

foo.jpg - the actual image

._foo.jpg - the resource fork data

Mac users don't see the ._ files since anything that starts with a period is automatically hidden. When you copy such files back to your Mac, they are recombined as a normal twin fork file.

So let your PC users know that all of the duplicated name items that start with ._ are nothing they need, or can even use. They can either ignore, or delete them.

FWIW, I know what the others are saying. However, try formatting the sticks to ExFAT - MBR. I just copied 42 jpgs to a stick on my Mac then plugged it into my Windows 10 machine and no "ghost" or invisible files.

No idea about dropbox.

I forgot something. I had show invisible files disabled in Windows 10. All I had was three invisible files from the Mac however. Not one for each jpg.

All I had was three invisible files from the Mac however. Not one for each jpg.

This is weird. I experimented with a flash drive formatted as FAT, and then ExFAT. Each time I put various files on it that should, and should not have resource fork data. Such as Photoshop CC, which does not write a resource fork. And yet, OS X creates a ._ file for every test item I put on the flash drive, which was randomly chosen stuff that was very recent, and from a very old CD written from OS 9.

No matter which way I did it, Windows 10 would show ._ AppleDouble files for everything I copied to the flash drive.

And yet, even with OS X set to show all invisible items, it would only show the hidden folders you see here.

That's confusing as heck to Mac users who want to see what hidden files or folders may be on a FAT or ExFAT formatted drive, and OS X refuses to show you the AppleDouble files.

Sorry Kurt, you've lost me (which isn't hard) lol

When I copied the 42 .jpgs to the empty flash drive all I saw were the 42 .jpgs. When I enabled "Show Hidden Files" in W10 I can see the .fseventsd, .Spotlight-V100 and .Trashes folders. Plus the 42 jpgs.

I assume you've already done this in Windows 10, since you mention you've already enabled "Show Hidden Files", but I'm going to be obnoxiously verbose just to make sure we're talking about the same thing.

With Cortona / Search open, type in "show hidden" (without the quotes). That should give you a match to open the control panel.

Turn on the radio button to "Show hidden files, folders, and drives". I also turn off the check box to "Hide extensions for known file types". I want to see the FULL name, not bird instead of bird.jpg .

With these settings in Windows 10, I see every AppleDouble file El Capitan creates. Which it does for every single file I put on a FAT, or ExFAT formatted drive. Even for files I know have no resource fork data. Or at least, aren't supposed to.

Not what I did although I assume what I did accomplishes the same thing. In File Explorer's view tab I just enabled or disabled Show Hidden Files. At some point I can copy files that should have two forks such as applications. I assume I will see more invisible files. It's obvious from your Windows screenshot you had a lot more on the flash drive than just jpgs which is what I thought the thread was about.

It's obvious from your Windows screenshot you had a lot more on the flash drive than just jpgs…

Yes, but that wasn't really the relevant part. I was wondering why El Capitan wasn't showing the AppleDouble files at all - for anything. Were they there, or not being created for JPEGs, or any other files? The result of the test was that, yes, El Capitan is still creating the ._ AppleDouble files, but won't show them to a Mac user even with viewing of invisibles turned on.

Disabling Show Hidden Files should suffice.

In File Explorer's view tab I just enabled or disabled Show Hidden Files.

Thanks for bringing that little tip to my attention! When did MS add that? I don't remember it being in Win 7 or earlier (never had 8 or 8.1).

With show hidden items on:

And off:

Much easier and faster than dinging around with the folder options dialogue box.