Just encountered the same problem today. Even went as far as creating a new VM from the latest version of hassio vhdx. This also fails at the same point.
Tried to disable ipv6 and still not working.
Any suggestions as what to try would be greatly appreciated. All was fine yesterday.
Fixed the problem by using the Virtual Switch Manager (in the Hyper-V Manager) to delete the virtual switch and create a new one.
No idea why this should work or if it was a coincident but this has fixed the problem for me.
I had this problem running HassOS in a VMware VM on Windows. I fixed it by disabling all the network adapters that the VM had access to but wasn’t using.
hi all thanks for the involvemenmt - gave up and bought a blue but did see that my exact mini pc has been used in this video Home Assistant PROXMOX Install and Setup (With NUC Alternative) - YouTube
Same here - VM in TrueNAS, I removed virtual ethernet adapter and added again with the same settings as it had. All good now. Thank you!
having this exact same issue on Oracle VM VirtualBox.
tried disabling network, reenabling it, switch from bridged to NAT,… no luck so far.
anyone any tips? 
ow yeah, it did work fine for about one day after installation.
ok… update… it works now.
must have been an issue with the settings in Virtualbox.
I was connected via ethernet cable, which resulted in the error described.
I disconnected the cable, so had my laptop connected via WiFi and now booting works fine and i have access again…
maybe this might help someone
Had the same problem. It looks that the problem is not related to Home Assistant OS. It a problem with Virtual Box Network Bridge mode. There is a problem with host WiFi interface that VB uses for network bridge mode. People says that they have the same problem with other OS images under Virtual Box. Just try to connect your host computer by ethernet cable and disable WiFi interface. That solution should work. Unfortunately I don’t know how to solve that problem with WiFI interface.
had the same problem after fiddling with Virtual Box network adapter. restarting my macbook did it for me. 
Having too many Bridge options was my problem as well.
Turned off all but what I needed and we’re golden, many thanks!
Found the solution for me :
“net update eth0 --ipv4-method auto --ipv6-method disabled” has worked in CLI and led to the solution of the problem.
Guts, IPv6 is causing some probs in my network?
I’m taking some detailed notes here to understand the heart of the problem so that it’s easier for others to identify that they have this same problem.
From another post I learned how you can “login” to the system shell.
ha> login
I also learned that network-manager is the tool used to manage network settings in Home Assistant OS; hence "Failed to start Network Manager’.
I’ve not really worked with network-manager before I looked for a guide to disable IPV6. Which I found an article from Red Hat discussing just that.
I ran the following commands hoping ipv4 would start working.
# nmcli set ipv6.method disabled
# nmcli set ipv4.method auto
# nmcli connection up "Supervisor enp0s3"
Nope, but it did give me a command to check logs:
journalctl -xe NM_CONNECTION=xxxx-xxxx-xxxx-xxxx + NM_DEVICE=enp0s3
I assume the command is unique per attempt.
Anyways the command spit out a lot of helpful information. Namely that the dhcp4 transaction was timing out after 45 seconds.
Given sembo’s post I might wager that the issue is at the link layer of the OSI stack since we don’t seem to be connecting into the network to get an IP address.
Update: the net tool does not exist in the VM and it looks like the above nmcli commands do the same thing as in sembo’s post.
Update: In general it’s not a good idea to use bridge networking with WiFi. The combination isn’t very compatible. Lots of VirtualBox forum posts about this. Most of these posts suggest using NAT.
When I do use NAT the VM is assigned an IP address. Just need to figure out how to access it 
If I ping the assigned IP I get requests timeouts.
There’s a great post in SuperUser about this issue with NAT: HOST can't connect to GUEST with NAT networking at Virtualbox but others. (I would link it, but I’m out of links )
The gist is this:
edit the NAT Network’s port forwarding. In VirtualBox manager, go to File → Preferences → Network and click the edit button for the NAT Network you are using. Click on Port Forwarding. Add rules that forward ports on your host machine to ip address + port on the guests (You don’t need to set the IP address for your host machine, that’s optional).
This is exactly what Vagrant does when you set config.vm.network "forwarded_port", guest: 8123, host: 8123. It would be so nice if HAOS was packaged as a Vagrant box. Working with Virtualbox directly is such a drag.
Update: The SuperUser post is outdated (like I said, a drag). You need to go to the settings for the VM > Network > Advanced > Port Forwarding. Then define a rule from 127.0.0.1:8123 to $GUEST_VM_IP:8123.
And now it works
TLDR:
Another Sad Update: If you use NAT the VM will not be in the same network as any device you would want to attach.
At this point I’m guessing you just have to have a wired ethernet connection.
Thank you, that fix my problem.
I’m also having a similar issue, however I’m running on a Rpi4b+, after applying the latest update (or trying to and rebooting) the docker daemon wouldn’t start. Trying to solve that lead me to here:
https://community.home-assistant.io/t/cli-not-starting-on-new-install/317855/40
But I cant parse the first command because my netowkrmanager isn’t running, which brought me here, however I notice my setup is a bit different and the solution above seemed to be a wired connection, which I’ve been running. When I try and run the above net update command, I get a response:
/bin/ash: net: not found
This fixed it. I also was only able to start my VMWare VM with cabled network.
Have the same problem with VMbox on a Win10 machine. I have changed nothing and updated nothing. But today I wasn’t able to connect to HA and this error message came up when I tried to reboot it.
I am already using a wired connection, so I have no clue what to do. Most comments above seem to address wireless connections.
Any suggestions?
I just had the same. In my case (Win10 + Virtualbox) it was not Hassio related. I had to find issue with my local network (which was strage as I had internet connection on other devices). I did couple steps including rebooting all routers/aps, disabling dhcp on one of the routers (I had it enabled on two for some reason), flushing dnses.
At the end of that reboot of server and reboot for hassio and now it worked.
I have just started using Home Assistant with a Dell Latitude laptop with Windows 10 and VirtualBox 7.
I can confirm that VirtualBox bridged mode with the Wi-Fi adaptor is unreliable, it works sometimes and not others and can be slow. I spent several hours trying different settings etc. but nothing worked.
After reading this post, I turned off the Wi-Fi and connected the laptop directly to my router via Ethernet and the responsiveness is significantly improved and now it just works.
I have added the Home Assistant VM as a shortcut to the desktop and then using the Windows “run” command then “shell:startup” I have added it to automatically start on boot up which so far works. I then have Team Viewer for remote access to the PC.
The solution consist:
instead of Network > Adapter 1 > Bridged Adapter, choose:
Adapter 1 > NAT &
Adapter 2 > Host-only Network
I’m not convinced that that is the fix.
After upgrading virtualbox from 7.0.14 to 7.0.18 and installing a Windows 10 upgrade I found I couldn’t get in to homeassistant, trying to access http://homeassistant.local:8123 just got a DNS error that homeassistant.local couldn’t be found.
Tried a couple of things from this article as I saw the ‘failed to start network manager’, changing from Bridged Adapter back to NAT, thinking that the VirtualBox upgrade might have changed things.
But setting to NAT didn’t work, and it contradicts Installing Home Assistant/Hass.IO (4.11) on Windows 10 (VirtualBox/Virtual Machine) - Community Guides - Home Assistant Community (home-assistant.io) which says you should set it to Bridged Adapter not NAT.
I looked at some older HASS VM’s that I had and they were all set to Bridged Adapter so it seemed unlikely that that was the fix. Per the install guide I changed ‘Promiscuous Mode’ from Deny to Allow All, but my older VM’s all had Deny on them and they worked at the time.
I suspect the issue I had was with my router because even though my Mercusys mesh wifi was all showing as online, I couldn’t get in to administer it, and I couldn’t access my solar inverters on the local network.
Powered the router off and on again, rebooted the mesh network, shutdown the VM and restarted it and its all working fine - with Adapter 1 set to Bridged Adapter and configured to use my on board ethernet connection. I have my windows 10 host hard wired to the router; connecting via wifi I quickly found was flakey