Lost All Files in a folder because of undo on my mac What just happened? I have a flash drive of mine with a lot of school files that I just planned on doing a format. So before I went to Disk Utility then erasing it to the format I wanted, First I backed-up all its files by creating a new folder on my desktop then just copy pasted all my files from the flash drive to this new folder I just created. Afterwards, I went on erasing my flash drive therefore losing all it's files but It's okay cause I did a backup anyways. 

Now when I was just about to put the the files from the new folder to the newly formatted flash drive, I was about to select all by doing shortcut command "command + a" I accidentally pressed "command + z" instead doing an undo and all the files were lost! After that, finder doesn't even allow me to do a redo! 

Please help those are a lot of important files now they're all gone in just 1 second and they're not even in the trash. I did a spotlight search of some files I can remember but I still can't find one!
If I understand the sequence:


you had files only on USB and no backup of those files
you pasted those files on to the Mac and we don’t know if you have Time Machine or other backup on the mac
you deleted the files on USB
the files for deleted off the mac (undo of paste is the suspect, but in the end, it doesn’t matter how they went missing)


The only saving grace or reason I would keep using a Mac in this situation would be to open Time Machine and see if there are any local snapshots to recover the data. If there was a local snapshot made any time after you pasted the files - they are easily recoverable - even if your “backup external disk” isn’t connected or mounted.

If you don’t have a backup, shut down the Mac and don’t run the OS until you’re sure you will or won’t pay to recover the files.


Recovering an accidentally deleted  folder in OSX - no Time Machine or backup available 
How to recover a deleted file on Mac OS X?