while copying files from windows hard disk to usb hard disk low space

I am having 476 Gb of a virtual machine and I am trying to take its backup in external USB disk.
Here is a screenshot telling the free space on my hard disk 379 Gb

and here is a screenshot of error which I get when I try to copy paste the virtual machine vmdk files from laptop to USB hard disk

here is size of virtual machine on USB hard disk 376 Gb

here is the screenshot of hard disk on laptop whose backup is to be taken 452 Gb

the difference of virtual machine on USB and laptop is approximately 76 Gb
and my external USB hard disk has 379Gb free space.But still when I try to copy paste the virtual machines vmdk files from laptop to external USB hard disk I get error as in above screenshot.
Which says there is not enough space on external hard disk ,you need 188 Gb to copy the files, where as there is 379Gb space available still I am not able to copy paste the files to external USB hard disk.
How to resolve this problem?

I use Windows 10 Home edition.

I believe that you are misunderstanding the message. The message does NOT say that you need 188GB of space. It says that you need an ADDITIONAL 188GB of space beyond what you already have.

Some things that you can do:

If your virtual disks have been in use for a long time, and if you do not have them configured to preallocate all space up front, you may be able to go into VMware and perform a defragment followed by a compact operation on the virtual hard disks. When I do this on my VMs it often shrinks the disk sizes considerably. See the VMware docs for details on accomplishing these steps.

what I did is those 25 virtual disks one by one I copy pasted them and then this time when I did manually one disk after the other firstly this error pop up did not came and then all the files got replaced by the files which I wanted to take backup. I do not know but this worked. Also before doing this I have deleted some files which Treesize tool (the tool should be run as admin) detected as files in hidden recycle bin folder on USB hard disk. How ever even after deleted the hidden recycle bin files I had this error but manually moving one by one files solved my problem.

Ah yes, I understand now. Windows didn't take into account that you were REPLACING files that already existed on the destination so it didn't accurately understand how much space was actually needed.

As an example, if you had a file on the source that is 110GB called "myfile" and you have a file by the same name on the destination but 100GB in size, since you are replacing a 100GB file with a 110GB file you only need 10GB of additional space but Windows may think that you need 110GB

I recently used DOS's MIR command to write over existing files adding changes, mirroring drives, and deleting files no longer on the source drive. It does not rewrite any data already on the dest. drive, it only modifies. Cool tool. DOS rocks. DOS's dcopy:T switch even maintains the original folder datestamps in the destination drive.