Wrong available space for network folder

[Caz]

Hi,

I am trying to sync/copy (sync through 1 line script or direct copy-paste) a folder from my local drive to a network folder but it fails because of supposed insufficiant free space.
Problem is: there is 1To free space and the folder is only a few Go.
I have tried with different folders and the same error occurs. Each time I have then copied successfully the folder through Windows Explorer.

Copying smaller folder works, the copy dialog box shows an available disk space of only 4.75Go.
Copying data with size below 4.75Go works but it fails for larger sized data.

I then tried mapping the network folder as a drive.
There the copy works. The available space is 1To in the dialog box as expected.

The problem seems that XY only sees 4.75Go of available space when copy-pasting from C: to \\network-folder.
When copying from C: to Z: (mapped network folder), the available space is 1To and the copy works well.

Any help will be appreciated.
Thanks.

[admin]

Run this script through the address bar (fill in your UNC path):
echo get("freespace", "[your UNC path here]");
What is returned?

[Caz]

4.72Go

[admin]

Strange, the free space function works without problems for UNC paths AFAIK.

That 4.72Go must come from somewhere. Are there any redirections, junctions, mount points in that path?

[Caz]

I have no idea. It is a network folder at work I would like to use as a backup location. I cannot ask IT for more info.