Copying large amount of small files cause issues

[capun]

XYPlorer 64-bit 28.10.0200
Windows 11 Pro 2H2025 up to date
Desktop scaling 100%

I am doing a 1:1 backup of some folders from one HDD internal drive to another HDD USB external drive.
Some of the folders seem to contain many thousands of small files with no extensions. File sizes are 1, 4, 5 kB and many more small sizes.

If I drag and drop the folders from one pane to the other pane with the option of "Backup Here", smaller folders work fine but some of the larger folders cause an error.

You get an message that an error occurred with a file at this location
C:\Users\MyName\Appdata\Roaming\XYPlorer64\Temp\
An example of the file name is CCF-20251225-175358.txt
It looks like a temp file with a log of the copy/backup activity.

This is the error message
Backup (Background Job #1)
Error reading temp file

If you press OK on the error message, the Backup operation stops
In some cases I cannot close the backup activity monitor and the only way to close it is via the Task Manager. It has an Xcopy task that needs to be ended to close it.

I don't know if there is a certain amount of files in the folder that causes this issue.

If I do an XCOPY command via the Command Prompt (Admin rights) it works fine,

[admin]

Interesting. This message has existed since 20231025, but nobody has ever reported seeing it. The same message can actually appear in two different places. The next beta will help me get closer to identifying the source of the issue. Please post the refined message when you see it again.

[capun]

I ended up finding the folders that were causing the hang, then copy them in batches. That method (what a PITA) worked.
I am doing another similar backup and post any issues.

[admin]

Wait for the next beta, it's not out yet.