MacBook Pro M1: Files vanish from LaCie external drive

Happened to me too. After searching the internet, I saw this particular message -

When an MP4 file disappears after being copied to an external hard drive on a Mac, possible causes include incorrect file system formatting, hidden files, drive errors, or even a 'move' operation instead of a 'copy.' Troubleshooting involves checking file system compatibility, verifying storage space, unhiding files, and running Disk Utility's First Aid.

So, what I had initially done was trying to move from my local disk to the drive, and it was taking too long, so I cancelled it. I tried other files and formats; they were copying fine. I did the same move operation again, and waited for it to actually kick off and complete.

Worked!

BTW, my drive was a Samsung T7 4TB and an Apple M4 Pro MacBook Pro.

cj1739 wrote:

I have a Macbook Pro M1 ands a LaCie 2tb external hard drive.

I'm trying to copy a couple of MP4 files (one is 600Mb and the other is 2Gb) from the Macbook to the LaCie.

The LaCie still has 1.1Tb of free space.

But when I transfer, it looks like the transfer is completing. The file name shows as grey on the LaCie whilst transferring, then when it completes the file name is black, but then after just one second the file dissapears from the LaCie drive

.

I've rebooted. I've run 'First Aid'. I've disconnected and reconnected the LaCie drive, but the problem keeps happening.

Can anyone help please? I was able to transfer files ok a few days ago....

Well there is no magically insight to your issue.

If you drag and drop could be you are moving the file...

If you hold the Option key and drag and drop you see the green+ mean you are moving a copy; so even if it gets lost or no access in your situation or what ever is going on you are not left with nothing.

I know there are some differnces here moving /copying file internally in Finder vs moving /copying files to external drives...

Experiment a a bit to see whats whats.

You maybe able to restore the originals if you have TM turned on — see local snapshots:

About Time Machine local snapshots

https://support.apple.com/en-us/HT204015

https://support.apple.com/guide/mac-help/about-time-machine-local-snapshots-mh35933/mac

blow by blow on local snapshots restore:

https://discussions.apple.com/thread/256253694?sortBy=oldest_first