UPDATE 09/04/21 - added info on the matter of having BTRFS problems on some x20 and x18 model

DO NOT update to 6.2.4 version if you have any of these models running BTRFS:


Synology has confirmed a problem with DSM 6.2.4 on selected models that have been reported for some users.

Synology community official info from Martin Chou (@martinchou).

The problem is that if you own any of the mentioned models with BTRFS volume already in place, and you update to the 6.2.4 version you will end up with a problem with your volume no longer accessible.

The problem is that the volume will register as a BTRFS volume while those models do not support BTRFS at all due to a "mistake" (as Synology calls it) that was in effect before 6.2.4.

You will be faced with the following warning:

DSM 6.2.4 volume problem on selected models

You will have only two options to get your data back:

  1. Migrate the HDDs to the model which supports the BTRFS file system (Recommend)

  2. Recreate the ext4 volume:
    a. Please contact technical support to mount the volume.
    b. Backup the data.
    c. Remove the volume
    d. Recreate the ext4 volume

A nasty bug from Synology side. Do not try and do any repairs yourself without consulting the support unless you already have a valid backup of your data.

UPDATE 08/03/21: New 6.2.4-25556 info added

UPDATE:  version 25554 is no longer, and it was replaced with version 25556, bringing these changes to the list:

  • Fixed an issue where external hard drives couldn’t wake from hibernation on certain platforms (Grantley, Broadwell, Broadwellnk, Broadwellntbap, Purley).
  • Fixed an issue where users could not sign in to Synology mobile apps after they had cleared the remembered device list in DSM 6.2.4.

Today Synology pushed out a new version of its current DSM 6 version tagged as 6.2.4-25554.

Hopefully, it will not get pulled, as this has started to become a popular move from Synology. Would advise you to hold off for about a week or 10 days before pushing this update on your device.

I have upgraded one of my extra devices today on day 1, the DS918+.

In case your DSM will still not pick up the update, you can get it manually from the following location for all models.


Here is the current info on the release:

Version: 6.2.4-25554

Important Note

Your Synology NAS may not notify you of this DSM update because of the following reasons. If you want to update your DSM to this version now, please click here to manually update it.
The update is not available in your region yet. The update is expected to be available for all regions within the next few days, although the time of release in each region may vary slightly.
This update will restart your Synology NAS.

Compatibility & Installation

  1. Enhanced the password policy. Passwords must exclude usernames and descriptions, include both upper-case and lower-case letters as well as numerical digits. The minimum password length is 8 characters.
  2. Fixed a compatibility issue between the Geminilake platform and virtual machines running Windows 10.
  3. On a newly installed version of DSM, file rename and deletion log events for SMB will be enabled by default.

What's New

  1. Users can now set 10 email addresses to receive system notifications.
  2. Enhanced domain database synchronization performance by syncing only altered data.
  3. Supports bad block detection on Synology SSDs.
  4. Supports the updating of Synology HDD and SSD firmware directly via DSM.
  5. Improved fan speed control based on the Synology network interface card temperature for 19-series and newer models.

Fixed Issues

  1. Fixed an issue where the "Enable Web Assistant" option didn't work on NVR216 and NVR1218.
  2. Fixed an issue where the date and time formats for scheduled tasks were inconsistent in the widget and system settings.
  3. Fixed an issue where scheduled tasks may fail to be executed or modified.
  4. Fixed an issue where tasks scheduled at a high frequency generated a lot of logs and occupied system partitions.
  5. Fixed an issue where the custom welcome text may differ on the preview and actual login page due to character limits.
  6. Fixed an issue where data could still be written to LUNs after the volume runs out of space.
  7. Fixed an issue where if Wi-Fi dongles are installed, some available network interfaces weren't listed when users edit iSCSI targets.
  8. Fixed an issue where iSCSI services may be unstable when the host is too busy or when users disable iSCSI targets and ending sessions simultaneously.
  9. Fixed an issue where initiators couldn't connect to the iSCSI target after ethernet interfaces reconnect in a high-availability cluster.
  10. Fixed an issue where packages may not operate properly when drives migrated from another Synology NAS cause volume ID conflicts.
  11. Fixed an issue where users may not be able to find their Synology NAS in My Network Places on Windows when WS-Discovery isn't operating properly.
  12. Fixed an issue where Log Center didn't record recycle bin enabling/disabling events.
  13. Fixed a security vulnerability regarding Sudo. (Synology-SA-21:02)
  14. Fixed multiple security vulnerabilities. (Synology-SA-21:03)


In response to the enhancement of domain database synchronization efficiency, the domain user/group list will be updated once an hour when it is created with Synology Directory Server.

So far there are no visible problems with the release, and the update took about 1min to perform (on an SSD array). Reboot was required, as indicated in the notes.

What's new

There are a few things that I would like to reflect on in this update. As you might be aware or not, Synology has started last year to push out its "own" SSDs, and HDDs, as well as NVMe modules.

In this patch, we have gotten a few "new" features regarding the new drives now being used with their new and current NAS models.

  1. Supports bad block detection on Synology SSDs.
  2. Supports the updating of Synology HDD and SSD firmware directly via DSM.

So looks like there are now options built inside the DSM that will help with bad block detection on their brand of SSDs as well as the option to update HDD and SSD firmware directly from DSM.

How will that look and work, I don't know, considering that I am not running with those drives at this moment, but it is nice to see these options coming in DSM.

Another new feature that was pushed in this version is the option to add multiple email recipients for email notifications, up to 10.

  1. Users can now set 10 email addresses to receive system notifications.
Up to 10 email addresses for your email notifications

Keep in mind that this will apply to all the notifications that you have setup. You can't decide what account will get what notifications.

Finally, as always, security fixes are last on the list. There were several in the past weeks not just affecting DSM but also specific packages and apps (Docker for example).

In this 6.2.4 patch, there is two security patch that is fresh and currently still ongoing for all the other Synology platforms, not just DSM.

Synology-SA-21:03 DSM

Synology-SA-21:02 Sudo

I will post an update on this article if there will be any reported major problems with this release.