What did Sonos Support say, when you called in with this issue? I watched about 6 hours of TV/movies last night, I had no interruptions on mine. 

Any chance it is a power issue?

Is the wall socket in good condition and wires tight?

Do you have a UPS you could plug it into to test?

Isn’t a power issue, I bought and arc ultra and moved this arc unit into another room. So it has gone from being connected to two rears and a sub to just a sub. It’s now doing the same thing it did previously. All devices are wired with wifi disabled.

Since ‘wired’ is the secondary method of connection, not the primary, I’d at least try it with the radios/wifi turned on, on all devices, just as a test. But I’d still call Sonos Support to discuss it.

Everything is wired with WiFi disabled because sonosnet is janky and causes loops if not configured correctly / requires RSTP to be disabled, legacy STP enabled and link costs enabled on switches. Would be great if SONOS could get with the times.

Uploading diagnostics to SONOS doesn’t help because the diagnostics only contain details from boot, and since it dies and reboots, those logs are lost. Is there any way to stream the logs out of this thing to another location before it dies to see what is causing it to panic?

I wouldn’t think logs would be lost over reboots, just factory resets, but I certainly don’t know for sure  where they’re stored locally, either. 

Have you tried, and gotten confirmation that they’re lost, directly from Support?

Loops, as far as I’m aware, are caused by multiple devices being wired to an improperly set managed  router. Probably Sonos Support can help you there, but I’ve only seen that occur when more than one device is connected. When on WiFi, there should not be any possibility of internet device ‘loops’. 

I’m suspecting an ARC intermittent hardware issue.

With respect to loss of diagnostic data because of a reboot, only the very latest details will be lost. There is a buffer of high detail that rolls over after approximately 10min. Longer term details, such as network setup changes will survive a reboot. To some extent a note that there was a network “error” of some sort will be kept for a while, but the immediate details will be lost when the buffer rolls over or is purged by a reboot. SONOS support can trigger additional data logging that will survive a reboot.

Until you are transferred to a higher level of support that can enable and access the enhanced logging, you can send occasional diagnostics on speculation. It’s mostly chance, but you might catch helpful, transient detail. Certainly, the string of diagnostics will expose network setup issues.

From what SONOS support have said, it only keeps logs from boot.

Is the current recommendation to use WiFi for everything or just use the soundbar as the ethernet bridge?

My Arc Ultra also has started rebooting itself randomly.  Just started doing it this past week. 

Call support and get a ticket opened. Sooner is always better.

So far my Arc Ultra is still rebooting randomly about once an hour on average sometimes more.  Unplugged the AppleTV and just tested directly from Apps on LG OLED G4 to Arc and the Arc still reboots.  Support has not been helpful other than suggesting to try a different HDMI cable.  Cable (8k high speed) and setup has not been touched since the initial install.  Swapped the cable and the Arc has since rebooted twice after that.  Am thinking I will move it to another TV to see if I can catch it rebooting on a different TV.  

Been submitting diagnostics which, per support, seem to just show that the reboot happened but not why. Asked what condition would cause the Arc to reboot on its own while TV is still powered on…...

Went through all the troubleshooting steps with support, replacing HDMI cable, resetting the Ultra, disconnected from TV entirely and it still will reboot on its own when playing music straight from the Sonos App. Shipping it to Sonos for a replacement. 

I went through the same thing. I understand them having to troubleshoot but it seems to either be a hardware issue within the Arc itself or the software build. I have three arc ultras in my house. One has been doing it for about two weeks and they just RMA’d that one and then one in my bedroom started rebooting itself last night. The issue now is that when the Arc reboots itself it drops other speakers from the room apparently and I Have to unplug those to have them rejoin the room. 

Yeah, I think its the first time me saving the original boxes has paid off.  You are on your own to box it up to send it back to them.  They do provide the RMA to cover shipping but they dont send you a box.  Mine just arrived at Sonos today.  Will see how it goes from here to get a replacement..

I did the advanced shipping and I will get that money refunded so when they ship me the new I will place the old one in the new box and send it their way. Somehow though, I do not think that is going to fix the problem. 

I havent had the issue with my Beam 2 setup (yet).  Although that one uses a usb-c to hdmi adapter to the sonos optical adapter from an iMac. 

Received the replacement Arc Ultra a few hours ago.  Hooked it up and added my sub and 2x 100s to it.  It just rebooted itself a few minutes ago while watching tv…….

Any chance you can switch it from the eARC to an optical connection to rule out the TV being at fault by sending commands that cause the reboot?

yeah I thought of that on the first Arc Ultra I sent back and completely unplugged the hdmi cable so it wasnt connected to the tv at all.  Just played music on the Ultra from the Sonos app while using a different power cord off another sonos speaker and a different outlet.  It still rebooted on its own. 

Since it’s happened with the replacement ARC as well … that to me, would imply that there’s something wonky about the power coming out of that outlet, or your whole home.  Have you tried connecting the ARC to a UPS?  That would help ensure you’re getting clean/consistent power.  And if that still doesn’t solve the issue, then, well … voodoo 

I tried a different outlet on the first arc I sent back.  Still rebooted. Both tv and arc in same outlet and tv is fine. Arc worked fine for several months prior to this issue. 

I hear you, but perhaps in the interim something has started going weird with the power in your home.  I imagine you don’t want to spend $$ on a battery UPS/surge protector but that could at least eliminate the possibility that the power coming out of your outlets is wonky enough to mess with the arc.

I also have era 100s x4, sub4, beam2, sub mini all fine no issues. 

I'd suggest the UPS option again too, seems like the other possible problems have been eliminated, leaving power as the next most likely suspect.

Nobody outside of Sonos engineering knows enough about the power supplies to have an opinion on why one Sonos on that outlet works and another doesn't. 

Removed all speakers from the room in the Sonos app, then moved my Beam 2 to the main room (replacing arc ultra that reboots) and added tv, 2x 100s, sub4 to it.  Same power, network, hdmi cable to same TV that the Arc Ultra was using.  So far no reboots after about 6 hours… Will see how it goes.