Help needed with Nucleus recovery:

Roon Core Machine

Nucleus (Rev B) w/Samsung 860 Pro 512 GB SSD
Purchased new in April, 2020

Networking Gear & Setup Details

D-Link EXO|AX AX5400 WiFi6 Gigabit Mesh Router
Connected to Nucleus via CAT 8 ethernet

Connected Audio Devices

Pro-Ject Pre Box S2 connected to router via CAT 8 ethernet

Number of Tracks in Library

Very few. Less than 100

Description of Issue


I have a Nucleus that has lost connection with my network. I’ve tried all basic tactics and it no longer shows as a connected client on my D-Link router admin dashboard.

I’m beginning to work the recovery process described on other support posts. I have a USB keyboard connected to the Nucleus and an HDMI monitor connected.

I currently have a Roon logo page displayed on the monitor (see photo), with two small squares in the upper right corner. Setup/Bootlist

What next?

That screen is a sign that your SSD holding Roon and the Roon Operating System is failing. It will need to be replaced.

I see that your Nucleus is now outside of the 2-year warranty period, so your best approach would be to purchase a new SSD to replace the existing SSD and install ROCK onto it. Start from step #3 in this guide:

Note that you’ll need to plug in a keyboard into the Nucleus to boot from USB.

Once you are up and running again, contact @support and they will arrange to have the ROCK version of Roon OS replaced with the Nucleus version - they can do this remotely.

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I think they simply work a little magic to add the passive cooling feature that Nucleus needs and is not included in the ROCK that you will be installing.

Thanks, Geoff.

If you get stuck @brad_thompson, I’ve assigned your case to me so I can monitor it. Please do let me know!


Thanks, Wes. I’m now studying up on the M.2 replacement. I see community posts regarding M.2 SSD upgrades and brand alternatives to the Transcend TS128. Can you recommend a proper brand and model to use?

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I’ll chip in here @brad_thompson and recommend Samsung, just very fast and reliable though not the cheapest. Other companies make some decent models but it’s a bit of a lottery. Never had a Samsung SSD fail on me in 10 years or more of using them.


Thanks, Killdozer. To be clear, I’m replacing a failed M.2 SSD…not adding an SSD for storage. Are you recommending I use a Samsung M.2 SSD? If so, what model would you recommend?

This would be a suitable model, IMO…

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Absolutely Brad, but I now appreciate I was slightly ambiguous. It’s basically the same tech and I own a few of both. I’ve just seen @Geoff_Coupe‘s suggestion, it’s a good choice.

Edit although having looked quickly this is a good buy with the sale price.

It’s the reliability that you’re buying over the performance. That said both are more than adequate. Sorry @Geoff_Coupe , I just got curious.


Trying to catch up on my notifications and you’ve got help just pouring in. I will concur with the others. Samsung is a solid choice. I have always had good success with Crucial too.


Update on Nucleus recovery: I’ve replaced the original M.2 SSD with a Samsung and it appears to be seated properly and recognized. I’m now attempting to flash the SSD with the ROCK factory reset image (roonbox-linuxx64-nuc4-usb-factoryreset.img.gz). Unfortunately, I’m stalled at the “Reboot” command. Any ideas? (the disk info screenshots are of the USB stick I’m using to transfer)

Thank you!

Hi, Wes. Any idea what I’m doing wrong with this Rock flash? (please see recent update)
Thank you!

@brad_thompson are you selecting the USB stick to boot from on the initial screen for sure? Press the down arrow key to highlight the line starting USB : Generic Flash Disk 8.07… and then press return.

Sorry, looking at the last screen, I suspect that you’ve not burned the USB stick properly. Bootable: No looks wrong to me. If my suggestion above doesn’t work, how did you prepare the USB stick?

Edit See these instructions and use Etcher on your Mac to prepare your bootable USB stick, specifically Section 4, Option 1:

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Thanks for chiming in. I followed the ROCK install instructions using my Macbook Pro and did the following:

  1. Using the disc utility application, I erased and formatted the USB to ExFAT.
  2. Using Etcher, I flashed the USB with the ROCK install file (roonbox-linuxx64-nuc4-usb-factoryreset.img.gz).
  3. I inserted the USB into the Nucleus, turned it on, and pressed F10.
  4. I selected the Generic Flash Disk from the menu and pressed enter.
  5. Arrive at the Reboot and Select command.

side note: I have no experience formatting and flashing USB drives. Did I miss something important in the formatting menu options? i.e. GUID partition map option vs. Master Boot Record option?

Thanks for all the help!

So I’ve never flashed ROCK myself, but I still suspect something’s wrong with your USB prep. You shouldn’t have to format the stick at all, Etcher should do that for you and set up the appropriate boot sector. Could you share screenshots of the Etcher steps please, that’s the key part.

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Or try another stick, if you haven’t already.

Etcher is 3 steps:

  1. select file
  2. select target drive
  3. flash

I’ll get a new USB stick and try some more.