I had exactly the same problem. Downgrading back to HassOS 5.4 solved the problem for me.
Ever since (3 weeks ago), it has been stable and no more network issues. Everything after 5.4 makes it unstable.
There are multiple Git issues raised, but none seem to make progress nor show any indication that someone is working on getting it resolved.
@Cazimbo , i now have it up and running again, downgrade tot V5.4 did solve this problem!
Are we the only who have this ??
I’m sure we are not the only ones. There’s enough tickets raised on Git about people with similar issues and there’s a few on the forum here as well.
Unfortunately it doesn’t seem like the issue has been identified, nor indication that anyone is actively looking in to this nor getting close to a solution.
The issue happened somewhere between 5.4 and 5.6 as that’s where I started getting issues.
Tries to change router - not helps. Maybe moving to ODROID or x86 is only solution?
Same issue here, installed it yesterday to test it out. Not the best first experience.
I ended with ESP8266 pinging PI and switch off relay to restart it 
one-two-three days lifetime and Pi hangs, cpu temperature about 70 degree after restart (59 before hang). If connected by ehernet Pi also kill all network activity on lan, restart helps.
Yeah i have a similair issue @Volume9, I have the red/white standard pi4 box which was getting really hot and killing off my network over LAN when it crashes, taking the ethernet plug out the back would instantly resolve the network activity.
Not had my pi crash for a week or so not sure if just lucky but tried a few things, which might be worth a look to see if this helps anyone.
Moved from Ethernet to wifi on the pi4, when I did this it no longer killed the LAN/router/network activity. But HA would still crash but at least to just homeassistant offline (then similair process to restart the power via smart plug offline).
Open the pi4 case lid to allow more heat to escape.
Disabled ipv6 completely and just leave it to connect over ip4 via the homeassistant backend settings (same place to enable wifi).
This is all running the lastest version of homeassistant supervisor (6.2?)
Moved from Ethernet to wifi on the pi4
yes, I do same thing for keep lan alive
Open the pi4 case lid to allow more heat to escape
I have Pi without case and with heat sink, temperature grow only after Pi already hangs(
Disabled ipv6 completely
Do same but it not helps
Also I tried to change power source, no effect
according to my observations, freezes occur more often after new version are available to update in supervisor page, this week no updates are available and it only hangs once.
Got you that makes alot of sense then, as before it was like every other day it was going down which is really frustrating, was strongly considering your suggestion for the ODRIOD move as maybe its just pi4 related but its not cheap 
as the pi4 does everything i need for now (when it works!)
There are lots of people with similar issues with the pi that started last November. Do a Google search to find the many open GitHub issues. A good one to start with is 1119. Two workarounds that seem to work with the people that have this freeze issue is revert to HAOS below 5.5. 5.5 changed the kernel and caused issues to a group of pi users. I was at 5.4 and never crashed. Above 5.4 never worked for a full day for me! The other option is change to Debian and HA as supervisor. I changed to this several months ago and again no crashes, freezes, etc. There is an excellent forum topic on running the pi4 on my Debian. Very clear directions and many people willing to help.
I’ve just set up Home Assistant and have had it running for just over 2 days. I’ve attempted to install Home Assistant several times in the past but have always ran into problems and given up in the end. This set up has been the most straight forward I’ve gotten, however the problem I am having is that each morning that I have gotten up to check Home Assistant, the Ethernet has become disconnected on the Raspberry Pi. The Raspberry Pi is on but the ethernet lights are not flashing, the problem is resolved if I unplug and re-insert the power. I did have the pi connected to a port on a Tenda wifi mesh node but I’ve swapped it onto a splitter running from a powerline adapter. I am sure I have had the Pi set up before in a similar manner and this hasn’t happened? Hopefully when I wake up tomorrow, it will still be online… Any thoughts as to what I could do? Is there a way of setting up wifi as a back up?
as bschatzow mentioned, supervised setup on Debian is a possible solution. But it’s are still posibility it can depricate in feature. It’s really strange for devs to leave one option for install on Pi, and this option so unstable.
I don’t think they will deprecate it again. There was to much reaction to that decision.
I have had the stability issues for almost a year. I shared many logs with the developers (@Stefan) and others. I opened GitHub issues that have remained open. I tried many custom versions that they made for me to try and none were successful. It is not that the developers aren’t trying to fix the issue it is just that the issue has only effected a select few of us. I am not sure if the developers have the necessary equipment to troubleshoot the issue correctly. I believe there is a timing issue on some of the pi boards due to variations of the component tolerances.
I have followed the issue closely and the only solutions that I have seen for anyone with this issue is as I posted above. As long as the users were using good hardware changing the power supply, SSD or controller never seemed to solve anyone’s problem
There has never been any useful log information to help solve the problem. Debian works for now. Who know what happens when this updates to 11 if it will continue to work?
I upgraded to Debian 11 when they announced support was coming Did not have any problems yet, but I did not have them before. The only issue is the ‘unsupported OS’ messages, but that will change once the updated supervisor is released.
Thanks. I am very Interested In hearing from people that had the issues with HAOS if they still have no issues with Debian 11. If they don’t then it will lead you to believe that the issues are caused by how the HAOS was implemented.
Hi All,
MY RPI4 lost connection in the local network (ethernet connection), when i check in my router, all devices are here expected RPI4. when i reboot my RPI4, it appear again in the network.
my router : Nokia G-240
I already set a static IP for HomeAssistant
have i miss something?
Thanks
This is exactly what happens to me.
The home assistant host disappears from connected clients in my router.
I have router connected to a tplink deco mesh system which confiured as dynamic IP. the RP4 board is connected to that bridge.
Hi,
it seems that this problem happen frequently, and a few hours later it appears again.
i use RPI4B ethernet connect to the router, the led is on in the router and RPI4 but canot found it in the local network, even if i use the static ip address.
i am having the same problem for 5 days now. and even with my new staging-homeassitant-raspi.
the strangest thing: the LAN-Port-LEDs stay ON, when i disconnect the cable. This seems to be a Problem with the network adapter driver in the Home-Assistant-OS.
Never had the problem with Raspian on the board
i had it always on before, because i used it as DHCP-Server.
i would revert to an earlier home-assistant-OS