After 1 month of usage, I suddenly noticed some of my apps that were installed in my HDD their icons were changed to a paper/note. I tried troubleshooting it and I found that in my Disk Management my HDD went from 1 TB to 3.86 unallocated. I tried reallocating it and it says: "The request could not be performed because of an I/O device error". Take note that I have scanned my HDD and it is still S.M.A.R.T capable, I have also checked if my PC still detects it through Device Manager and it is still detected. What is the problem and what caused my HDD to be 3.86GB unallocated? Is there a fix or is it dead?