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

Same problem here. It has taken 8 weeks to finally pinpoint the problem, i.e. Monterey 12.3 and using Finder to copy files from my MacBook to my NAS.

When using WiFi, files are copied successfully with exact same byte size. However, similar to OP, I started getting intermittent video glitches on my TV/NAS setup (which had been fine for 5 years) start, from approx early April onwards. I used 'cmp' to report the files are different, although byte count was the same

No video glitches when using ethernet to move the files from MB to NAS. 'cmp' reports files are identical.

Grrrrrrrr. As mentioned above, why doesn't Monterey 12.3 verify the file?

I am currently having this problem, after I copy a video file using finder it will not copy correctly, as confirmed with md5 check.

When I used terminal to copy with "ditto" command however it worked without issue. It is a completely new issue on a mac mini that I have been using for years. I thought it was external HD I was using so I got a new one but I have the same issue.

I'm definitely following this issue. I'm having the same problem. My regular scenario for years was moving files downloaded onto my Mac over to a network drive used by Plex. My family started complaining a couple months ago that videos were glitchy and I spent an embarrassing amount of time trying to figure out why. First maybe was it an issue with Plex but that wasn't it because playing the files directly off the drive without Plex Media Player would have the same glitches in the same place.

Ultimately, I did what you did which was to compare the hex in both files from my local drive on Mac to the network files (even though they were exactly the same size to the byte) and it was a mess. So the problem is exactly what you are describing with copying files from my local drive to network drive -- but mostly really big video files.

My temporary fix has been to download the files directly to the networked drive from my Mac without dealing with Finder. That has cleared everything up but it's a workaround to a silly problem.

My solution is that I use the old unix command cp from the terminal window. Use the -r flag to copy directories recursively (including all files and subdirectories). Here is how you do it:

1. open terminal
2. type "cp -r " (without the quotes)
3. drag the file or directory you want to copy from the finder into the terminal window. The full path and filename should appear in the terminal.
4. drag the destination drive or folder into the terminal. The path should appear as the second argument to the cp -r command.
5. hit the return (enter) key
6. wait until the copying is finished. You won't see any progress bar, but when it is done, your prompt will reappear in the terminal window.

I was having the exact same problem today while I was copying large video files to my TrueNAS server. After hours trying to figure it out the problem I stumbled upon your post and confirmed it was Finder corrupting my files. I made a simple test by copying a 1.5GB to a thumbdrive and boom, the file was corrupted. Compared both using the cli tool diff and they weren't the same file. Restarted the Macbook and now it works fine.

I have been using the free open source muCommander to copy files and it's been working perfectly (it's a bit clunky though). It's an alternative to Finder. I'll keep posting here and keeping an eye out until this bug is fixed. I'd much rather use Finder.

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.

Additional point to note:

1) Using MD5, my files are corrupted when copied via WiFi from a MacBook (APFS on Monterey 12.4) to a Raspberry Pi 4 (OpenMediaVault with an external EXT4 hard drive)

2) No corruption when copied over hard wire ethernet. Yay.

3) I will report back if I get chance to test with a USB stick or WiFi to another machine.