Windows Explorer Drive Usage reporting mm

A Windows 10 computer has 4 external USB drives connected, a 1TB and 3 2TB drives. 2Tb drivers have shown their good performance in the reported Used Space,

The problem which I am facing is The hidden Recycle Bin folder for this drive has been emptied. System Restore is not storing any Restore Points on this drive. Windows Backup is backing up to one of the other external drives.

However

Disk Manager reports the drive is Healthy, and 1.18TB of space is used.

“This PC”, 1.18TB Used.

Any ideas which were appreciated on the cause of such a great difference in reported usage?
It’s serving me 1TB of unavailable space that otherwise appears to be unused.

Thus anyone has any ideas to resolve it because everyone doesn’t have the same ideas as I have so please appreciate me to resolve the problem

Thankful to all of you guys
regardfully lot of joy