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There may be several reasons for this phenomenon, please refer to the following countermeasures to troubleshoot the problem:

1. Check whether the TNAS and the PC are in the same LAN and in the same network segment.
2. Reinstall the hard disks into the TNAS in the original order, turn it on, and try to search again.
3. Take out the hard disk, turn on the empty machine and wait for about 1 minute, then try to search again.
4. Connect the TNAS directly to the PC and try to search again.
5. Check whether the firewall is turned on on the PC. Please turn off the firewall and try to search again.
6. Before moving, you may have set the firewall of TNAS to only allow access to a certain network segment, which resulted in inaccessibility.
If so, please connect the TNAS directly to the PC, and then change the IP of the PC to the IP of the network segment that allows access.

Guys, my expiriens at this way say next: look at Control panel - General setting section- Security - Security Isolation mode. Disable it mode.
Remember where are you enable this function - come back to this LAN and disable it.
TM wrote notes: ... outside local network segment... neeb be read as ...ONLY THIS local network segment... (not another).
I hope TM some change notes at this mode and put some FAQ - how to disable it via local console in near future.
WBR, Sergo.

Hi all,

I think i have screwed up my F4-424 in a similar way. I set it up back in November and I think I used the exclusive mode as discussed above for better security.

This weekend i set up a new Eero based network using wifi 6. My old network was a google wifi on 5. Everything seemed to go well, but my TNAS is not found in any of my TNAS PC or Mobile. I suspect I set it to exclusive and now the network has changed. I have no way to redo the old network nor remember any of the data.

Is there any way to save my TNAS and files or did I effectively brick it? (And my hdd i was using for external backups corrupted too...)

Any suggestions would be great.
Duncan

vadersson wrote: ↑14 Jul 2025, 08:54

Hi Duncan, please follow our instruction to reset it then check if your TNAS can be detected.
viewtopic.php?t=7178

Thanks for the response. I tried the article you linked to, but it did not seem to work. I don't appear to have an M.2 ssd installed, and I never heard three beeps when holding the reset down.

Any other suggestion? Should I try the remove hard drive steps listed above maybe?

Thanks,
Duncan

i had an idea. Could I install an M.2 SSD in one of the slots on the motherboard and reinstall TOS on that M.2 drive and then access the main hard drives in their Raid configuration? I tried the idea above of removing the hard drives and with just the empty TNAS did show up in my TNAS Mobile device. I don't want to loose my data on the drives, but it seems like the TOS installed on them seem to be the issue.

Thanks,
Duncan

You can install NAS on the new SSD, start it up normally, and then insert the old hard drive to read the data.

Thanks, that is good to know. I did not see any specific information for how big an M.2 NVMe SSD I can install. I assume you don't need a ton of space to run TOS out off. Do you have a recommendation for and M.2 NVMe size to run TOS?
Thank you,
Duncan

Hi all,

Another update. I just installed a 1TB M.2 stick on the motherboard. I started up the system with the old HDD out so as not to risk my data. Then I initialized the system. I can now access the TNAS and have TOS installed in the M.2 SSD. However, when I put the HDDs back in, I can't access them. I see them listed as Volume 2 with 10 TB of storage and 2.16 TB used, but I can't find a way to access them. Is there something else I need to do to be able to access the old HDDs?
Do I need to reset the M.2 and try and initialize the unit with the HDDs in? I don't want to wipe them. Is there anther way to access the volume 2? I just can't figure it out.

I will also point out that the Security Advisor in TOS shows that NOT having Isolation Mode enabled is a risk. That is probably why Isolation mode is on in the TOS installed on the old HDDs. Might want to clarify that there are risks with Isolation Mode in the future.
Thanks,
Duncan

You can find the option to restore shared folders in the advanced settings under Control Panel - Shared Folders, and choose to restore to Volume2.