I’d been having long boot times (which you probably know, and I find, often means HDD issues), and had just gotten a CHKDSK run request for the “problem” HDD at bootup, before I tried to run DOSDLG.
(Since CHKDSK both checks for bad sectors and for filesystem errors, I like to run HDD diagnostics before CHKDSK [particularly since in some cases CHKDSK’s filesystem effects can be catastrophic]. And for good measure I ran a full battery of hardware diagnostics: CPU, RAM, all HDDs.)
So next I did run CHKDSK on the drive, but the issue remained.
From this point my test results were weird. I removed the HDD but the long boot times
remained. I got a CHKDSK run request on my other 4TB HDD at bootup; I forget if I then ran CHKDSK but the long boot times remained.
Then I disconnected all but the system drive and the long boot times disappeared. I reconnected
the drives one at a time and the long boot times never returned!
Now, quite confused, I just booted to the USB drive and DOSDLG doesn’t say either 4TB HDD is “not supported”!
This all seems so mysterious I shall now run a repeat of my full battery of hardware diagnostics (CPU, RAM, all HDDs) before filing this issue mysteriously resolved. I’ll report back. Currently I’m wondering if I had a loose connector.