Can't Transfer MKV files to my External

So incredibly frustrating, Apple! I have same issue. 2 Seagate external HD attached to Mac Mini. Both HDs are exFAT. Trying to copy files from 1 to another and all will work until the job gets to a mkv file and then it will just hang up...wait for 5-10 minutes and the entire job will fail.

What a complete joke Apple has become. Literally can not even copy and paste files anymore.

One example that failed was a 11.75 GB .mkv and another is a 3.92 GB .mkv. I am attempting to copy and paste from one external exFAT hard drive to another external exFAT hard drive.

It's especially frustrating that when it fails on one file, the job doesn't just keep going. The job hangs up and fails and then I realize it hours later and have to start all over again until the next .mkv hangs.

1. FAT has a 4 GB limit. exFAT does not. exFAT file size limit is 16 EB.

2. The files are already on an exFAT drive. Trying to copy from one to another. Had no trouble writing them the first time by a Windows machine so should not be an issue with exFAT.

3. One of the two files that failed is under < 4 GB but that shouldn't matter given that exFAT does not have a 4 GB limit but a 16 EB limit (it is FAT that has the 4 GB limit).

4. The only differences I can think of are that the original drive with the data is made by Western Digital (WD) and was formatted exFAT by a Windows machine vs the new drive that I am trying to copy to is made by Seagate and was formatted exFAT by Mac OS Sierra.

5. This appears to be specifically an issue copying MKV files to an external exFAT HD.

-36 is premature end-of-file. That is almost always a problem with the source.

Based on that, the reason you cannot make copies of these files is because the source directory is corrupted or the file is damaged.

See if Disk Utility (repair) or (First Aid) can do anything for directory corruption. If nothing, you will have to use Terminal chkdsk command.

All of those address directory corruption only. They do not look at the actual file, only the directory.

It is probably worth a try to attempt to duplicate the file on the same drive. But you are likely to run into the same error. If you do, that shows the source file is very likely the problem.

Great idea! So I tried to copy and paste the .mkv file in a new folder on the original drive...so the source files must be corrupted. Wow. They were written to the exFAT drive by a Windows machine so who knows the root cause at this point. Thanks for your help Grant.

I do wish the copy job wouldn't fail at the first corrupted file, but would skip that file and keep going. Is there any way to run this job? I'm moving 4 TB of data that is 1750 files so if the job fails one #5 in the list of the 1750 then I have to delete that corrupted file and start the job over again. Maybe I'll get lucky and there are not any future corrupted files in the 1750, but who knows!

Anyway to run the job and have macOS just skip the corrupted file and keep trucking vs fail and stop?

If you were working on a MacOS Volume, it is more likely to tell you the file is damaged, and do you want to continue to copy the others.

Regardless, you could manually copy the files in smaller groups. You can ask for several sets of copies one after the other and they will all be done concurrently, and they will just stack up in a progress window in the Finder, adding a new progress bar for each set of copies.

This is the error code given. Not sure if source or destination.

How is the external drive formatted?

If it is formatted FAT32 then that is the problem, if the files are over 4GBs in size.

FAT32 can only handle files 4GBs or less in size.

And if it's formatted NTFS, that's read-only to the Mac OS unless you install a third-party NTFS driver such as Tuxera NTFS or Paragon NTFS.

Go into Disk Utility and re-partition it and format it Mac OS Extended (Journaled) with a GUID partition table.

Reformat the drive. (Note: this will erase everything from it, so back up its contents to another drive first.)

If you will use it only with Macs, format it Mac OS Extended. If you must use it with Windows PCs too, see whether your version of Disk Utility offers the option of formatting it ExFAT, and if so, use that format.