After reformatting my Seagate Replica 2 TB external hard drive, I loaded some files back on to it. It now still shows 1.81 TB of 1.81 TB free.
Possibly because drives are specified in terabytes (1k = 1,000 bytes) and Explorer uses tebibytes where 1k = 1024 bytes. So your 2tb disk says 2 terabytes on the label and 1.8 tebibytes when examined by Explorer. It's actually 10 to the power of 12.
You will have some relatively small system files on there after formatting, but who knows what your 'some files' means.
Let me explain better. In "this PC' view the drive is listed as 1.81 TB free of 1.81 TB. When I open the drive I can view the 6.6 GB of files on it. So how can it be 1.81 TB free?
Well I don't know everything. Consider that 6.6 gb is only 0.0066 of a terabyte, so it could just be rounding (e.g 1.814 less 0.006 = 1.808 rounded to 1.81).
Using properties on the drive will give a more accurate figure.
OK thanks. guess it is just too small an amount to show other than through "properties"