File this under Weird: In Monterey copying a file with Finder corrupts the data in the target file

I'm still having problem, and it is mostly MKV files but has also happened with MP4 and AVI files. I've been using cp from the terminal to copy now, and it is just really sad when an OS can't get a simple "copy" right. No telling how many of my videos have been corrupted when moving them off the laptop and onto a backup drive. It is a major data loss and I guess Apple doesn't care about data integrity if you aren't storing the data on THEIR computers. Definitely going to switch to Linux as soon as I make room for a new computer.

I did a short test but could not repeat the issue:

In macOS 12.5 I Finder-copied the same 1.86 GB .mp4 movie 9 times back-and-forth between Mac mini 2018 internal SSD and an external APFS SSD but the hashes seem to be the same (see below).

Can you repeat the issue at will? Does this happen only when Finder-copying to a server? Or to another folder or volume? Via USB or Ethernet or Wi-Fi? Which file system? How large files? What is the best and easiest way to verify the hash error, preferably between multiple files in input vs output folders?

ls -al
-rwxrwxrwx@ 1 *****  staff  1862672600 Jul 24 20:32 1_generation.mp4
-rwxrwxrwx@ 1 *****  staff  1862672600 Jul 24 20:32 9_generation.mp4

md5 1_generation.mp4
MD5 (1_generation.mp4) = 7dba3f80abc532570bd8954b14a7c0d9
md5 9_generation.mp4 
MD5 (9_generation.mp4) = 7dba3f80abc532570bd8954b14a7c0d9

shasum -a 512 1_generation.mp4 
16b6262e57b125cde2b0afee71b3a3fbfeadc16b9dd3a0dbd0678dfc4950fb39b205269c2d18e4330a92b21cef17e4309d3e7e31a1ae7de3dd5190b39ea06745  1_generation.mp4
shasum -a 512 9_generation.mp4 
16b6262e57b125cde2b0afee71b3a3fbfeadc16b9dd3a0dbd0678dfc4950fb39b205269c2d18e4330a92b21cef17e4309d3e7e31a1ae7de3dd5190b39ea06745  9_generation.mp4

I confirm the problem with copying files through the Finder on macOS Monterey 12.5. When copying videos through the Finder, the files are not the correct size and lags start when playing videos on any player. There are no problems when copying the same files via One Commander.

Unfortunately, I have no solution. But this is the same problem I've been having since March 2022 (after I updated Monterey to 12.3). Hope this can shed some light on the problem at least.

I have a MacBook Air early-2020 (Model: A2179) and an iMac 2017 (Model: A1419, upgraded to 32GB RAM). Both installed with macOS 12.5.1 current, WiFi and wired network via AirPort Extreme (ME918Z/A) and AirPort Time Capsule (ME182Z/A).

This error occurs on both Macs, I have three LaCie d2 10TB external drives (series linked via Thunderbolt 3), one LaCie 2big RAID 28TB (USB-C) and one NAS Synology DS920+ 64TB (Wired network cable) all drives are Seagate IronWolf Pro HardDrives as all formatted to APFS except NAS which is Synology's "BtrFs" format as JBOD.

I've spent countless hours trying and troubleshooting, unplugging one drive after another, but then after a while, it happens again. Tried on both MacBook and iMac, happens anyway after a while. Can't find any pattern, other that if I copy a file to another disk, I never know if it's broken unless I test it extensively. I move many 100 video files in from large projects, and do not have any opportunity to check each individual file after transfer. Have lost over 20TB of footage and at least 1k working hours of edited video material which is now lost forever. Because I found out after a while that the copying had failed, but after deleting the originals. 🙈 So I have not been able to work properly since I found this out since March 2022. All my work is at hold, since I can't use the disks as they should. Even sent a drive to Seagate to use their recovery service and have the drive replaced, as I was sure it was the one causing all the problems. To discover soon after, that the problem was still there! I have also sent in the iMac for service, but the Apple workshop found no faults and did not change anything. Again costing me precious time and money. Googled for many hours to find something about this, but never found any useful info until this thread. 😉 Also spent several tens of hours with Seagate customer service. Seagate has really tried everything, as I was sure it was the drives until recently (now). But it makes sense that this could be a software error, so now the iMac should be downgraded to MacOS Big Sur asap. So maybe this will finally stop 👌, as I don't dare move a single file as it is now. Also spent countless hours on troubleshooting, becoming increasingly puzzled as the error occurs on all disks, but never know when and where it happens.

The only pattern I've seen is that it doesn't happen right away right after a reboot/or recently connected an external disk. And that it mainly applies to video files. When the error first occurs, if I copy the same file to each of the disks: all will contains the exact same error (for example missing 5 frames after 30 seconds) on each of the files on all the disks even the original file are fine! If I unmount the source disk, and unplug the power for 10 seconds. Then I connects again, then everything works perfectly fine again until suddenly it happens again. 🤯 And the file can be copied to any disk without missing the same error as in the example. It can take 10 minutes after you connect a USB disk, or it can take a week. But happens every time I move somewhat large projects etc (as several hundred GB or a few TB).

Incredibly frustrating, this is what I mainly do om my iMac/LaCie drives and have all this expensive equipment for. This error has made everything worthless to me. I have no words for how frustrated I am. Have almost exclusively used a mac since 2007, if it turns out that this is a software error. Then they have at the very least suffered a setback in my eyes Sorry for my bad Norwegian-English.

Hi

have you tried the solution some users on this post are offering ?

Using an external files manager to transfer the videos instead of using finder

i am currently on a trip but I’m eager to give it a try once I get home

No, but thanks for the input. I will be doing it this week asap. 😊

Incidentally, have also tried reinstalling macOS Monterey without installing anything else or from a backup. This bug also happens then.

I'll keep you updated if downgrading to Big Sur works.

Thank you very much for your reply Brianrh7. 😉

Just confirming I also have this issue.

it doesn’t matter if I’m copying to or from internal/external drives, the file gets corrupted (hash changes).

As a test I downloaded a really obscure video, and it still got corrupted, so I can’t see this being Apple knowing they are dodgy files!

It only does it with video files, not .ISOs etc.

It has nothing to do with whether the file was downloaded via BT.

A couple of days ago one of my LaCie 10TB HHD failed big time, the one drive that I never suspected (under two years old). The one that has worked perfectly all the way. As soon as I disconnected it, the problem disappeared. Unable to provoke the error any more, so it's probably the disk that has provoked all these strange errors for five months. I never got to test the bug properly in macOS Big Sur, at this happened the same day i downgraded til Big Sur. Now everything seems to work perfectly again in macOS Monterey 12.5.1 (provoked the system with coping files from the one disk to another for two days now, all works fine). Then it was probably just a hard drive that caused it, no software bug(s). Finally it looks like I can start working again. 🥳 Very happy that I think I have found the bug after almost 6 months of troubleshooting. 😅 Thank you for for listening to my complaints! 🙈 Take care!

I guess the error was just a start of a failing disk who failed for some time (about 6 months before it revealed itself)!

How interesting and you may have guessed that I also have QBitTorrent. So are you saying that somehow QBT was preventing Finder from transferring the files correctly? How could the two things even be connected?

So in theory, if we downloaded a bunch of videos on the the older version QBT, then uninstalled QBT, Finder would have worked properly? So very confusing but I'll update and try it out again for sure now. Thanks for the update.

I have also been using QBT. So it is possible that the old version QBT was corrupting the file in some way, however Finder is still at fault for corrupting the file further. Why does the "cp" command from the terminal work just fine without corrupting the file, yet Finder drag and drop corrupts the file? This is still a problem with Finder.