Drag and drop won't move ALL selected files between Finder windows Here's what I'm doing:


open a Finder window with source directory (500+ files).
open another Finder window with target directory.
select all files in source directory using ⌘ - a
grab selected files and hover target window
press ⌘ so files are moved instead of copied
release mouse button


But only cca 85 files are moved. Rest is left in source directory (while still selected). The same happens when copying files.

Is this something I can change (number of files moved)? An error/bug? Some app interfering with drag &amp; drop behavior? I'm left with using Terminal to move my files, which besides being annoying isn't really possible when file selection is not a simple ⌘ - a.
I know this is late but I've found a fix.

First, open disk utility and run first aid on your disk. 

Second, shutdown the computer fully and disconnect all USB devices.

Third, Press the power button and hold command-option-p-r until the Mac reboots again. This will reset the PRAM. 

I hope this fixes your issue like it did for me!