Veracrypt full-device volume produces read & write errors hours/days after mounting

[erikblake]

Description

I have a 4TB M.2 NVMe drive that I mount as a device volume in VeraCrypt (to be clear, Windows sees the drive as having no partitions - shows as uninitialized). I am currently running VC 1.26.24, but the volume was created using an earlier version of VC. The problems are recent and started happening months after upgrading VC.

When initially-mounted, the drive functions normally, but after a period of time (hours, days, maybe after a few hibernations/sleeps) accessing the drive begins to throw errors. This only started happening a few days ago, and may be associated with a Windows update (Win11 x64 Enterprise).

• When trying to create a folder: An unexpected error is keeping you from creating the folder. It you continue to receive this error, you can use the error code to search for help with this problem. Error 0x8007701B1: A device which does not exist was specified Note that I can continue to read from files, when this happens, just not write.
• Trying to save a file on the volume fails. No specific error. For example, Excel will say Error were detected while saving XXXX.
• Sometimes trying to open a folder results in an error (my apologies for not noting the specifics).

The problem is resolved by unmounting the drive, rebooting the computer, and re-mounting the volume. If one skips the reboot, then VC/Windows throws the error A device which does not exist was specified. Source: MountVolume:9093 after entering the VC mount password.

When the problem occurs, I always attempt to dismount the volume before rebooting. Though first closing all programs that could be accessing the VC-mounted disk, I always need to specify a forced dismount. When re-mounting the disk after reboot, I sometimes get the warning that the filesystem was not cleanly unmounted (even though I did do so) - thankfully chkdsk has yet to find any issues with the VC filesystem once scanned and remounted.

Expected behavior

Filesystem, mounted on device continues to read/write without issues

Observed behavior

After some period of time has elapsed, read and write errors begin to occur.

Screenshots of saving a file, or creating a folder shown below. See also description above.

Steps to reproduce

1. Boot computer
2. Open VeraCrypt, select device (entire NVMe 4TB SSD), and mount with password
3. Wait for a variable amount of time - sometimes hours, sometimes days. Laptop need not sleep or hibernate to reproduce the issue (though screen saver does come on during inactivity), but doing so seems to accelerate the issue.
4. At some point, folders on the drive begin to read as empty, saving files causes errors, and creating folders throws "device not found" errors.

Screenshots

Your Environment

VeraCrypt version: 1.26.24

Operating system and version: Win 11 64 25H2

System type: 64-bit ZBook G10A laptop