[Help] F4-425 Plus – Repeated Sudden Power Loss [SOLVED]

[EriChan]

Please continue to observe whether the problem reoccurs after removing the UPS. If the issue reappears, first restart the device, then download the debug log and send it to our technical support email ([email protected]). After receiving it, our engineers will analyze the log and provide a solution.

If possible, please record the time when the problem occurs, as this will be very helpful for our troubleshooting.

Additionally, for a quick response, please include the forum link and your ID.

[nantwich425]

Quick update on the F4-425 Plus random power-off issue.

I’ve now removed the UPS from the setup and confirmed the system is connected directly to mains power. The issue is still under investigation and I’ve enabled debug logging to capture any future events.

Current configuration:

2 × WD Red Pro 8TB (media volume)
2 × WD Black SN7100 1TB (OS/apps volume)
1 × WD Black SN7100 1TB (cache for media volume)
1 × WD Black SN7100 2TB via USB (backup target)

HDD hibernation is enabled, and I have scheduled backup jobs running overnight (USB + cloud). It appears that during backup windows, all HDDs spin up simultaneously from idle while NVMe and USB storage are also active.

Notably, the Red Pro drives have higher spin-up power requirements than standard NAS drives, so I’m currently testing whether peak power draw during wake/backup transitions could be a factor.

No shutdown logs are present when the system powers off, which suggests a hard power loss rather than a controlled shutdown.

Will update again once I have debug logs or further isolation results.

[TMzethar]

Okay. When you send the debug logs to the technical support email, please also include the system report generated from the “Technical Support > Report Issues” section.
Files that are too large cannot be sent as email attachments. In this case, we recommend sharing a link via cloud storage and sending it to the technical support email address.

[Burnacid]

Mine got replaced, It's still stable after a week. Fingers crossed

[CursaYang]

If there are any abnormalities, feel free to contact us again.

[nantwich425]

Hi all,

Just to close the loop on this — the issue is now resolved.

I deliberately waited a couple of weeks before replying to make sure this wasn’t a false positive. Since making the change, the NAS has been completely stable with zero unexpected shutdowns.

Root cause

The problem turned out to be the UPS.

I was using an APC BE850G2, and after removing it from the setup and plugging the NAS directly into mains power, the issue disappeared entirely.

What was happening

This UPS performs periodic battery/self-tests. During those tests, it appears to briefly transfer load or introduce a small interruption. That momentary drop was enough to cause the NAS to lose power instantly (no logs, no graceful shutdown — exactly like pulling the plug).

This kind of behaviour isn’t unheard of — there are other reports of UPS interactions causing odd shutdown or reboot behaviour with TNAS systems .

Outcome
Removed UPS → no more crashes
Same hardware, same workload → fully stable
Suggestion

It may be worth reviewing the APC BE850G2 for compatibility (or at least flagging it), as it doesn’t seem to provide a seamless transfer for this device and could lead to unexpected power loss.

Hopefully this helps someone else chasing the same issue

[Gremlin]

I'm not familiar with this particular model, but the transfer time is listed as 6ms typical and 10ms max*. If you have a windows machine you should be able to re-configure the ups via APC's Power-chute software to turn off self-test function. (Once configured you can revert to the nas connection) You might also look into adjusting the voltage sensitivity of the ups to see if that makes a difference.

* similar to other models