Cannot complete formatting standard VC container file in Windows mount point of ISCSI volume

Topics: Feature Requests, Technical Issues, Users Discussion
Dec 2, 2015 at 12:36 PM
As a TrueCrypt user for many years I now wanted to switch to VeraCrypt.
System: Win7 Pro SP1 64-Bit fully patched, VeraCrypt 1.16 64-Bit (VC)

I want to use standard VC file containers which are to reside in a volume mount point for an iSCSI volume formatted as standard NTFS. This is because drive letters are a very limited ressource on Windows systems :-)

In Disk Management the NAS volume via iSCSI looks as follows:

Properties as invoked from Disk Management:

Here's how it is mounted instead of using one of the sparse drive letters:

From a Windows Explorer perspective:

All the standard tools are there ... defrag, check, actually the mounted iSCSI volume checks out perfectly fine:

I can copy whatever 'normal' files I want, delete, move around - no issue. What I cannot do is create a standard NTFS formatted VC container in c:\mount\iscsi-nas23, here is how it goes:

The only thing I can do is created an unformatted container, like those 2 test containers here:

I can even mount the container like this:

But when I try to format using Windows it fails like this:

Formatting via command prompt is a bit more informative:

Curious enough it is possible to format the very same test containers when the iSCSI drive is presented to the system not via a folder mount point but as a regular drive:
But ... drive letters are scarce and thus the folder mount option would be much more fitting, I think.

Furthermore, after formatting, it is also possible to remove the drive letter of the iSCSI host volume again, present it to the system in a mount folder and successfully mount the NTFS formatted container files in VeraCrypt, but it seems the drive has issues when mounted in this way - it is, for example, not possible to run a full checkdisk without error message.

This is the error-message from checkdisk when the container is mounted from a mount point folder:
1037161 freie Cluster verarbeitet.
Verifizierung freien Speicherplatzes ist beendet.
Fehler beim Schreiben mit Status 0xc0000002 bei Offset 0x40000c00 für 0x400 Bytes.
Unbekannter Fehler (6e74667363686b2e 11e1).

When checkdisk runs on the same container file mounted in VeraCrypt from drive letter X: all seems well:
Verifizierung freien Speicherplatzes ist beendet.
Das Dateisystem wurde überprüft. Es wurden keine Probleme festgestellt.

4194047 KB Speicherplatz auf dem Datenträger insgesamt
 21568 KB in 6 Dateien
    12 KB in 13 Indizes
 23819 KB vom System benutzt
 23024 KB von der Protokolldatei belegt
4148648 KB auf dem Datenträger verfügbar
  4096 Bytes in jeder Zuordnungseinheit
1048511 Zuordnungseinheiten auf dem Datenträger insgesamt
1037162 Zuordnungseinheiten auf dem Datenträger verfügbar

Is this a known issue? Should one not use folder mount points with VeraCrypt?

It would be very nice indeed if would be possible to use mount points instead of drive letters.

Please advise if this can be made to work.