TerraMaster Forum

Hello everyone,

I am experiencing a serious SMB issue on my TerraMaster F4-425 running TOS 7.0.0804.

External USB drives used to work normally over SMB with macOS Finder. Now, whenever I connect an external USB drive to the TNAS and access it from macOS Finder, browsing becomes extremely slow, Finder hangs, and Samba repeatedly crashes.

This issue is **not limited to one specific USB drive**. I have confirmed the same behavior with external USB storage in general. The 4TB exFAT SSD mentioned below was simply the main drive used during detailed troubleshooting.

## System

* TerraMaster F4-425
* TOS 7.0.0804
* macOS client using Finder
* SMB
* External USB storage
* Main test drive: 4TB exFAT SSD

## Important Diagnostics

The external USB SSD itself is healthy and extremely fast when accessed locally on the NAS.

Local filesystem listing:

`time ls -la "/Volume1/@usb/usb_Extreme Pro" >/dev/null`

Result:

`real 0m0.002s`

So the USB drive and filesystem are not slow.

I also tested SMB locally from the NAS itself using `smbclient`.

After entering the password before the timed test, a clean SMB connection and directory listing completed in approximately:

`real 0m0.068s`

Inside an established `smbclient` session:

* The root directory appears immediately.
* `Motion Templates.localized` opens immediately.
* Its subfolders appear immediately.
* A newly created test folder on the same external USB SSD also opens immediately.

Therefore, SMB directory access itself can be extremely fast.

## The Problem Happens with macOS Finder

When macOS Finder accesses the same external USB share:

* Finder becomes extremely slow.
* Folder browsing hangs.
* Existing NAS SMB shares may temporarily disconnect.
* Samba repeatedly crashes.

The Samba logs repeatedly show:

`PANIC: assert failed`

`ls_named_stream(smb_fname)`

`INTERNAL ERROR`

`dumping core in /var/log/samba/cores/smbd`

The crash log shows Samba version:

`4.15.13-Ubuntu`

The crash occurs repeatedly when Finder browses the external USB share.

## Troubleshooting Already Performed

I have already tested the following:

* Confirmed the external SSD is healthy.
* Confirmed local filesystem access is extremely fast.
* Confirmed local `smbclient` access is fast.
* Confirmed the issue is not limited to one directory.
* Created a completely new test directory and file on the external drive.
* Tested different external USB shares.
* Cleared macOS Finder/cache data and restarted the Mac.
* Tested WebDAV as a comparison.
* Tested NFS, but the external exFAT filesystem could not be exported normally.
* Disabled `fruit:aapl` globally with:

`fruit:aapl = no`

The same `ls_named_stream` Samba crash still occurs.

The problem therefore appears to be specifically related to the interaction between:

**TOS 7 / Samba / macOS Finder / external USB storage**

## Expected Behavior

Before this problem appeared, external USB drives connected to the TNAS could be browsed normally and quickly from macOS Finder over SMB.

The expected behavior is that **any supported external USB drive connected to the TNAS should work normally through SMB**, just like the internal Data24 and Data30 shares.

This functionality is very important to my workflow and is currently preventing me from using external USB storage normally with the TNAS.

## Support Case

I already contacted TerraMaster Support by email and provided a full TOS System Report through Google Drive.

My first detailed report was sent on August 10, 2026, followed by clarification and follow-up messages, but I have not yet received a technical response.

I am posting here in case:

* another F4-425 / TOS 7 user has experienced the same issue,
* this is already a known Samba/TOS bug,
* TerraMaster has a hotfix or updated Samba package,
* or there is a recommended configuration/workaround.

If TerraMaster staff need additional logs, Samba core dumps, test results, or configuration details, I can provide them.

Any help would be greatly appreciated.

Thank you.

Sultan

Update – TerraMaster Support Recommendation Tested, Issue Still Not Resolved

I would like to provide an update on this issue.

TerraMaster Support contacted me and recommended changing the SMB protocol settings in TOS from:

Maximum SMB3 / Minimum SMB1

to:

Maximum SMB3 / Minimum SMB2

I applied the change exactly as requested, restarted the Mac completely, and tested the external USB drives again.

Unfortunately, there was no improvement.

macOS Finder is still extremely slow when browsing external USB drives connected to the TNAS, and Samba continues to crash with the same error:

PANIC: assert failed
ls_named_stream(smb_fname)
INTERNAL ERROR
dumping core in /var/log/samba/cores/smbd

I have already replied to TerraMaster Support with the test results and screenshots showing the SMB3 / SMB2 configuration.

A complete TOS System Report, including system information and logs, was also provided to TerraMaster Support earlier.

At this point, this issue has been affecting my workflow for more than 10 days, and normal access to external USB storage through macOS Finder is still unavailable.

I am therefore waiting for a deeper technical investigation, a confirmed root cause, or a hotfix/workaround from TerraMaster.

I will update this thread if TerraMaster Support provides a solution.

If anyone here has experienced the same issue with TOS 7 + macOS Finder + external USB drives over SMB, any additional information or workaround would be greatly appreciated.

Thank you.

sultan wrote: ↑14 Aug 2026, 16:15

To help us accurately diagnose this issue and confirm whether there is an anomaly within the TOS system, we recommend scheduling a remote technical support session with our engineering team.

Please contact our online technical support via the link below. When reaching out, be sure to include this forum post link and your forum ID so our engineers can quickly reference your context and assist you directly:
https://salesiq.zohopublic.com/signatur ... 97d0be8892

Thank you for your patience and cooperation!

I followed the instructions provided by TM Support and contacted the online technical support using the recommended link.

Unfortunately, the support channel only connected me to an automated assistant. The assistant explicitly confirmed that it cannot transfer the conversation to a human support agent, cannot arrange a remote engineering session, and cannot provide a direct engineering contact method.

Since TM Support specifically recommended a remote technical support session with the engineering team, could you please provide a direct method to schedule this session, or arrange it from your side?

I have already completed all requested troubleshooting and provided the complete TOS System Report, Samba crash logs, screenshots, and test results. The issue has now been affecting my work for more than 10 days.

I am ready to cooperate with the engineering team and provide remote access at any suitable time.

Forum ID: sultan

Thank you.

sultan wrote: ↑14 Aug 2026, 19:20

When you click the link to a livechat, you can click the "Talk to an Agent" at right down corner, then you can have a human agent for your service.

Please also update your TOS to the latest version viewtopic.php?t=10446,this version optimized some storage managment features, it worth to have a try.

This may be completely unrelated however...

What type of USB connector are you using? I was having problems sharing my USB drive at all with the USB-C connector. So I thought I'd try plugging my drive into a USB-C to USB-B dongle and connecting with that. Still no luck. Then I flipped the USB-C connector over and then it started working! Hmmm. Doesn't seem like that should matter but... maybe??? I then moved it back to the USB-C plug (without the dongle) in that same orientation and it seems to be working. Hmmm, not sure what to think.

I have discussed with TNAS that they put in security measures so that we are unable to access files on USB External Drives because it could cause a security issue.
For those of us who keep entire libraries (e.g. PLEX OR Mac Documents) on their external drive for ease of transport when needed, this is NOT a viable nor useful fix.
They tell me "we'll fix it in an future OS Update" - but they haven't for the past two updates.
This is a HUGE issue - WHY even include a USB port if it's unuseable? TNAS, PLEASE...FIX THIS NOW!!!!
I have many friends who access my PLEX movies, tv shows and music - which is on that Extternal USB Drive. Now NO ONE, including myself, is able to access ANY of those files.
A HUGE step backward for TNAS. It truly requires repair immediately!

ARThornicroft wrote: ↑22 Aug 2026, 23:55

Thanks for following up. This issue is fixed and will be in next week’s release.

I truly hope so. For me, I had reported this issue to TNAS Support since the OS update in late July (approx. July 25th), when we could no longer access anything on the external usb drive. It's now been 4 weeks, so the sooner this is fixed and updated via OS, the better.
Thank you.

ARThornicroft wrote: ↑23 Aug 2026, 23:19

You can try downloading this installation package, manually installing it in the App Center, mounting the USB drive, restarting the multimedia software, and then rescanning.

Storage Manager installation package：https://download2.terra-master.com/stor ... _amd64.deb