Hard Drive full? The case of the missing 1.5TB

MBR or GPT?

These articles should explain the mystery of your 'missing' drive space...

• https://www.seagate.com/support/kb/why-does-my-hard-drive-report-less-capacity-than-indicated-on-the-drives-label-172191en/
• https://www.howtogeek.com/123268/windows-hard-drive-wrong-capacity/

I had a long article typed up and my browser crashed, so I lost it all. Much sadness.
However, 4.8TB+788GB=a full 6TB drive.
The missing 1900GB is unusual. Download Partition wizard and see what size your partition actually are. Maybe you have unformatted space which windows cannot see?

Maybe you have system protection turned on?

https://www.tenforums.com/tutorials/4533-turn-off-system-protection-drives-windows-10-a.html

"Checking in the "My PC" under windows explorer, it showed that I was at max limit, but the space occupied was reducing by about 1GB a second without me doing anything."

That seems suspicious.

Personally, I'd suggest to reformat the new drive, setup partition, view size, then just leave it connected to your computer (doing nothing with it) -- and watch to see whether the space occupied changes by itself over time. Like, check right away, then 10 minutes later, then keep checking back every once in a while to see whether anything changes. I'd even leave it connected for a day and come back & check. Either everything is fine or you'll mysteriously start losing space. Once that's figured out, step 2 might be to copy over 1 large file, check the size right away, then leave the drive connected without doing anything else to it, and checking back periodically for size changes.

I do have a suspicion there might be a virus doing stuff to your drive, e.g. adding files or encrypting your files.

what cluster size is set when formatting a disk?

Some possible causes:

• Corrupt drive.
• Faulty drive.
• Fake drive that reports more than it's physically available.
• The missing space is wasted. For instance a badly chosen allocation unit size value when formatting the drive. You can check by selecting the files on the drive and comparing in Properties the Size and Size on disk values.
• Virused computer.
• Communication issue. Try changing the cable or switching to another port.
• Badly configured BIOS settings yielding unexpected results.
• Software conflict. Try booting in safe mode and checking the result.
• PC Hardware fault. Try the drive in another computer and see if it works properly.
• Broken/Wrong Drivers. Try installing the most recent drivers if available, preferably from the drive's manufacturer.

Dead platter.
8TB = 4x2TB platter?
If one platter is dead or mostly kaput you are left with 3x2TB maybe?

Glad you got it solved :)

Hmm, that is an annoying problem for sure :D I will keep the solution on my mind :)

I wouldn't say it was just a visual problem, something got messed up somehow (and in most cases once you got it fixed it stays fixed, but there could still be some underlying hardware issue, but that you won't know until it happens again or use some software like Crystaldisk).

Hi. I think checkdisk should be used once regularly when there was power shortage or some other sudden crash, seems more like filesystem/allocation problem (/f), such scan doesn't take long. Much longer is physical scan but if there is not other problem you don't need it (chkdsk /r).
I would suggest to install for example crystaldisk free software to monitor smart of your hard drives (in option change values from 16hex to 10dec for better clarity of reported data). You will know more in what state are your drives, if there are instable sectors or not.

Try the program WinDirStat, it shows all the contents on your drive and how much each folder takes, including hidden files and system files.

Even though it was solved, I'm an anal about finding the truth. So before the fix, did you happen to have a different user using the PC as well? If I recall correctly, if you tried checking a different user's file, it wouldn't show the size.

Or maybe the drive was corrupt and had a couple of bad sectors, which /f and /r would've "fixed" them. That being said, from my experience, if a hard drive had started to go bad, it's best to lose the drive rather than lose your files.