chkdsk in fix mode(-s) does not work and errors on NTFS drives on USB memory stick

[kriukas]

Dear Author,

May I provide some feedback about great Ext4Fsd driver:

When below conditions are true:

1. The physical drive contains several partitions. In my case - 3 partitions from Linux-based router, ext4; ext4; ntfs;
2. The Ext4Fsd 0.71 (base; not recompiled with latest changes) is installed and "Ext2Fsd" FS driver is loaded and running;
3. You put in such drive (in my case partitions are on USB memory stick) into Windows 10 machine (in my case latest ESU build version 19045.6809) USB port;

The following unproductive behaviour is encountered:

1. Windows OS errors out wanting to fin NTFS partition. It is not able to. Windows Event Log Entries are provided at the end of this post.
2. It is not possible to chkdsk from command line/shell such a partition in any non-read mode. Errors are encountered.
3. If the partition actually was quite cleanly unmounted (e.g. no active writes to partition, in my case - USB stick physically removed during router reboot right when all status LED lights go dark), then partition chkdsk in any read-only mode does not find any issues.
4. Partition is completely usable from all usual daily activities.

Workaround, used since Ext2Fsd 0.6x versions:

1. By any comfortable means like Ext2Mgr Auto-start/Service management / registry, service editing software (my case System Informer), set 2 services: Ext2Mgr and Ext2Fsd from auto start to demand / manual start.
2. The outcome: Ext2Fsd driver does not "grab" any non-system drive, which has at least one NTFS partition and usual Windows NTFS workflow takes over, which allows to use chkdsk as usual. Ext2Fsd can be started as needed.

Caveats:

1. Once Ext2Fsd is started, it grabs all drives NTFS partitions.
2. Even if all drives letters are removed, the drives did not use write caching, or any caching in principle at all (Quick Removal), no processes have open handles to any secondary+ NTFS drives, Ext2Fsd service cannot be stopped/unloaded. Don't know if that's even possible to unload FS drive without restart, but if there are no open handles - why wouldn't?...
3. Don't know, how the FS driver is written, but perhaps it would be possible for it somehow to disassociate itself from all NTFS partitions either on all drives, or by some criteria - like white/blacklist, newly inserted drives, etc.

1 ------------------------------------

Log Name:      Application
Source:        Chkdsk
Date:          2026-01-27 00:39:43
Event ID:      26226
Task Category: None
Level:         Information
Keywords:      Classic
User:          N/A
Computer:      xxxxxx
Description:
Chkdsk was executed in scan mode on a volume snapshot.  

Checking file system on E:
The type of the file system is NTFS.
Class not registered

A snapshot error occured while scanning this drive. Run an offline scan and fix.

Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Chkdsk" />
    <EventID Qualifiers="0">26226</EventID>
    <Version>0</Version>
    <Level>4</Level>
    <Task>0</Task>
    <Opcode>0</Opcode>
    <Keywords>0x80000000000000</Keywords>
    <TimeCreated SystemTime="2026-01-26T22:39:43.7604458Z" />
    <EventRecordID>61222</EventRecordID>
    <Correlation />
    <Execution ProcessID="0" ThreadID="0" />
    <Channel>Application</Channel>
    <Computer>xxxxxx</Computer>
    <Security />
  </System>
  <EventData>
    <Data>

Checking file system on E:
The type of the file system is NTFS.
Class not registered

A snapshot error occured while scanning this drive. Run an offline scan and fix.
</Data>
  </EventData>
</Event>

2 ------------------------------------

Log Name:      Application
Source:        Chkdsk
Date:          2026-01-27 00:40:37
Event ID:      26226
Task Category: None
Level:         Information
Keywords:      Classic
User:          N/A
Computer:      xxxxxx
Description:
Chkdsk was executed in scan mode on a volume snapshot.  

Checking file system on E:
The type of the file system is NTFS.
The shadow copy provider had an error. Check the System and Application event logs for more information.

A snapshot error occured while scanning this drive. You can try again, but if this problem persists, run an offline scan and fix.

Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Chkdsk" />
    <EventID Qualifiers="0">26226</EventID>
    <Version>0</Version>
    <Level>4</Level>
    <Task>0</Task>
    <Opcode>0</Opcode>
    <Keywords>0x80000000000000</Keywords>
    <TimeCreated SystemTime="2026-01-26T22:40:37.4625713Z" />
    <EventRecordID>61224</EventRecordID>
    <Correlation />
    <Execution ProcessID="0" ThreadID="0" />
    <Channel>Application</Channel>
    <Computer>xxxxxx</Computer>
    <Security />
  </System>
  <EventData>
    <Data>

Checking file system on E:
The type of the file system is NTFS.
The shadow copy provider had an error. Check the System and Application event logs for more information.

A snapshot error occured while scanning this drive. You can try again, but if this problem persists, run an offline scan and fix.
</Data>
  </EventData>
</Event>

3 ------------------------------------

Log Name:      Application
Source:        Chkdsk
Date:          2026-01-27 01:00:44
Event ID:      26226
Task Category: None
Level:         Information
Keywords:      Classic
User:          N/A
Computer:      xxxxxx
Description:
Chkdsk was executed in scan mode on a volume snapshot.  

Checking file system on K:
The shadow copy provider had an error. Check the System and Application event logs for more information.

A snapshot error occured while scanning this drive. You can try again, but if this problem persists, run an offline scan and fix.

Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Chkdsk" />
    <EventID Qualifiers="0">26226</EventID>
    <Version>0</Version>
    <Level>4</Level>
    <Task>0</Task>
    <Opcode>0</Opcode>
    <Keywords>0x80000000000000</Keywords>
    <TimeCreated SystemTime="2026-01-26T23:00:44.0552761Z" />
    <EventRecordID>61247</EventRecordID>
    <Correlation />
    <Execution ProcessID="0" ThreadID="0" />
    <Channel>Application</Channel>
    <Computer>xxxxxx</Computer>
    <Security />
  </System>
  <EventData>
    <Data>

Checking file system on K:
The shadow copy provider had an error. Check the System and Application event logs for more information.

A snapshot error occured while scanning this drive. You can try again, but if this problem persists, run an offline scan and fix.
</Data>
  </EventData>
</Event>

4 ------------------------------------

chkdsk C:\system\_mounted_fs\ntfs\on-usb /v/f
The type of the file system is NTFS.
Volume label is NTFSas-SDA3.

Stage 1: Examining basic file system structure ...
  312 file records processed.
File verification completed.
 Phase duration (File record verification): 9.45 milliseconds.
  0 large file records processed.
 Phase duration (Orphan file record recovery): 0.41 milliseconds.
  0 bad file records processed.
 Phase duration (Bad file record checking): 0.48 milliseconds.

Stage 2: Examining file name linkage ...
An unspecified error occurred (696e647863686b2e 532).
An unspecified error occurred (6e74667363686b2e 17b4).

[kriukas]

P.S. The function / URLs / methods to make any kind donations for further development would be greatly appreciated both in the software GUI itself and in this project info page.

Thank you for your time devoted, attention and spirit in any case! Kudos and may the force be with you ;-)