How to identify drive device from event log (Harddisk#\DR#)?

Question

I have a messages about drive errors in the Windows Event log, like this:

Bad Block On Device \Device\Harddisk0\DR0

I have two hard drives in the system. How can I know which one causes these errors? I see nowhere the same identification type, like there.

For example, the following are dialogs from Device Manager:

Can I be sure it is drive C since it is "Disk 0"?

Answer 1

You can be certain that the error message \Device\Harddisk0\DR0 is referencing Disk 0 as listed in the Disk Management MMC (Run > diskmgmt.msc). The Harddisk# syntax always refers to the disk number, but keep in mind this will be the disk number involved in the error message at the time the error was logged. If for any reason the offending disk's number changes between the time of the error and when you review Device Manager, you would blame the wrong disk.

Answer 2

The Harddisk# and DR# number both refer to a Drive (not a Partition or Volume)

• this is normally a physical drive (HDD, SSD, USB)
• each Drive may contain multiple partitions each of which may have a drive letter

As stated the Harddisk# item matches the Disk# id shown by Windows Disk Management.

The numbers are allocated in real time as disks are detected or connected.

For internal HDDs, both the Harddisk# and DR# number normally remain fixed (unless you swap motherboard socket connections).

Harddisk# numbers for removable drives (flashdrives and USB drives):

• the next available number is allocated during connection (filling gaps if present)
• if a drive is disconnected the number is removed leaving a gap
• once a drive is disconnected there is no record of previously allocated numbers

The DR# number is also dynamically allocated but follows different rules:

• numbers are allocated sequentially and are not reused while Windows is booted
• each time a removable drive is disconnected and reconnected the DR# number increments

Initially the Harddisk# and DR# number will match:

• but active use of removable drives causes the DR# numbers to rise
• only when Windows restarts does the DR# number allocation get reset
• the DR# number is not reset during User Logoff events only at a Windows Restart

Once disconnected there is no way to tie a DR# number to a physical device. A removable drive may have been allocated many different DR# numbers in the past.