MacBook Pro battery died during 1.2 TB file transfer, now stuck at 413.38 GB - How to find and delete copied files?

If unchanged from last night, I would click the x to cancel that task.

If the Macbook battery ran out of power during write operations, the external drive may have had its file system damaged. Is the external drive receiving its power from the laptop. To check for that damage, run Disk Utility First Aid on the external drive. It should complete with no errors mentioned. If it offers to repair the disk, have it do that.

What evidence do you have that there are ghost files?

I would verify the disk is clean with Disk Utility First Aid. Then I would restart the copy with stable power for all the drives and for the laptop. If a file already exists with the same name during the copy, have it overwrite all those duplicates. For this copy, instead of using Finder, which does not perform well for enormous copies of scores of files, I suggest that you make a "clone" copy using SuperDuper, which is free for the minimal featured version which is all you need. It's a good program to have with the full f featured version so I also suggest you buy a copy. You can alternatively use Carbon Copy Cloner, which is not free but also is inexpensive.

cragsjo wrote:

yes, major idiot move on my part. I didn’t note the starting total file size on the 4 TB drive. Just that I can’t find any copied new files in Finder…

Why don't you do a Get Info or run Disk Utility to see how much space is being utilized on the SSD in question? Then compare to the folders and files you can see, if they roughly agree, there are no copied files to worry about. Or simply list the files on the destination to see what, if anything, got copied. Or simply redo the copy and if it asks, tell it to overwrite any existing files with the same name as ones being copied. This is not a complex issue to address.

If you're going to be copying or moving lots of files regularly then I recommend you either learn how to use rsync or get something like Carbon Copy Cloner or Backuplist+. In the case where a copy/move is interrupted you can just run rsync again and it will only process files that haven't been transferred or have changed. rsync is powerful and comes with a daunting list of command-line options ; the two apps I referenced are user-friendly front ends for it. Others are probably available.

cragsjo wrote:

Looking, but not finding any successfully copied files to the 4 TB drive… 413 Gigs! So am thinking that Apple is hiding all that until the complete successful copy over??? That’s a lot of ghost files….

Usually a restart of the Mac clears out those leftover pieces. I think running the battery to zero can cause a disorderly shutdown (or sleep) and thus whatever was possibly copied is suspect. Has the SSD free space decreased by 400 GB?

A whole lot more familiar with windows brain surgery- decades experience, Pascal, Unix, C++, microprocessors etc programming courses versus 2021 my first foray into Mac and duly noted

Well, Windows brain surgery is fine, but trying a large file copy on a laptop with inadequate charge sounds like a basic boo-boo!

I personally would probably start over again, not knowing if any got corrupted by the low power copying.