Argon2id resume fails with ResumeInPlaceEncWaitThreadProc:408 on non-system volume

[persoyt111-tech]

VeraCrypt version: 1.26.29
OS: Windows 11
Volume type: Non-system volume, internal HDD, in-place encryption
KDF used: Argon2id
PIM: Left empty (default)
Keyfile: None used
Hash/Cipher: default / not noted

Summary:
In-place encryption of an internal non-system hard drive was interrupted
at approximately 5% completion after [précise ici : ex. "a Windows
restart" / "a forced shutdown" / "clicking Defer"]. The volume cannot
be resumed or recovered afterward — VeraCrypt consistently fails to
decrypt the volume header with the correct password.

Error message:
"Operation failed due to one or more of the following:

• Incorrect password
• Incorrect Volume PIM number
• Incorrect PRF (hash)
• Not a valid volume
• The volume uses an old algorithm that has been removed.
• TrueCrypt volumes are no longer supported.
  Source: ResumeInPlaceEncWaitThreadProc:408"

Steps to reproduce:

1. Start in-place encryption of a non-system internal HDD using
   Argon2id KDF with default (empty) PIM.
2. Interrupt the process at low completion percentage (~5%) via
   [décris la cause exacte de l'interruption].
3. Relaunch VeraCrypt — it correctly detects an interrupted process
   and prompts to resume Encrypt/Decrypt.
4. Select "Encrypt", enter the password, select the correct device.
5. Operation fails immediately with the error above.

Expected behavior:
Encryption resumes normally from the last processed sector.

Actual behavior:
Header decryption fails every time, even though:

• The password has been verified correct via copy-paste (ruling out
  keyboard layout/typo issues)
• No keyfile was used
• PIM was left at default (empty)
• The correct device/partition was selected (verified by size/ID)

Troubleshooting already attempted (all failed with same error):

• Retyping the password directly
• Copy-pasting the password from a text editor to rule out input errors
• Closing all applications with potential disk access, including antivirus
• Restarting the system before retrying
• Restore Volume Header using the embedded backup header (Tools >
  Restore Volume Header, no external backup file) — same 408 error,
  suggesting both the primary and backup headers fail to decrypt
  identically with this password

Possible related issue:
This may be related to #1614 ("Possible Argon2id incorrect derived
key"), which describes header decryption failing with Argon2id KDF
despite using the correct password, in a controlled test case.

Data risk / urgency:
The volume was only ~5% encrypted when interrupted, meaning the vast
majority of data on the drive is still in its original unencrypted
state. However, without being able to resume or properly decrypt via
VeraCrypt, the drive currently cannot be safely used or accessed
through normal means.

Additional info:
Happy to provide further logs, a memory dump, or test with a
reproducible sample container if that would help diagnose whether
this is the same root cause as #1614.

[idrassi]

I see that the report still contains French placeholder text ([précise ici ...], [décris ...]), so I need clarification before treating this as a confirmed VeraCrypt bug.

That being said, the source location ResumeInPlaceEncWaitThreadProc:408 means VeraCrypt failed while opening/decrypting the selected device using the embedded backup header in order to identify an interrupted non-system in-place encryption. This happens before the actual resume operation starts.

Please stop any write operations to this disk for now and do not try “Restore Volume Header” again on the affected partition. For an incomplete non-system in-place encryption, the embedded backup header is the working recovery/progress header: the primary header is not expected to be valid until the process finishes.

I need a few details to understand whether this is a reproducible VeraCrypt issue or a recovery case:

1. How exactly was the process interrupted: VeraCrypt "Defer", normal Windows restart, Windows Update restart, crash, forced shutdown, or power loss?
2. On the resume password page, was the KDF left on autodetection or explicitly set to Argon2/Argon2id? Was PIM left empty?
3. What exact device entry did you select during resume: the partition/volume entry or the whole physical disk?
4. Is this an official VeraCrypt 1.26.29 x64/ARM64 build, installed or portable?
5. After the interruption, was the partition resized, reformatted, checked/repaired by Windows, moved to another enclosure, or otherwise modified?
6. When you tried "Restore Volume Header" using the embedded backup header, did VeraCrypt report that the header was successfully restored, or did it fail before writing anything? Please provide the exact error/source shown for that attempt.
7. Can you reproduce this on a disposable test partition/VHD using Argon2/Argon2id, empty PIM, and interrupting only via VeraCrypt "Defer"?