Hello Same here. My 32 Gb SD Card has no more Space. My Backup is 900 MB.
I installed a fresh System on 128 GB Card and tried several times to install the Backup.
After a few hours no response from IP:8123
After a reboot the Onboarding Page is back…
Can you get to a console? SSH? And, are you running Supervisor (not sure if you can on a Pi or not)?
Go to the console and type:
supervisor logs
Mine took a while. I am running it on an old quad core server and the backups are on a Samba Share. So, it took a while. But, I expect it to take much longer on a Pi.
Here is my output at the end:
Hi.
I have a very strange problem. Let me explain it:
I’ve just made a backup from my RPI4-HA 2023.10.3 using Settings/backups in order to use it in a new instalation as a container too in another equipment.
II expected that after installing HA on the new device, there would be a “restore” option, but I only get the screen to install from scratch.
I was expecting the option that should appear, right?
I have the same problem but my backup it 3.1GB (not sure why until the latest release it was about 1.1GB). Now I struggle to backup on the Pi so I’m trying to move to a VM on a bigger system, but the backup cannot be uploaded to the new server (it errors out at 3.05 GB) or just gives a http 400 error.
Really disappointed that the backup and restore functions are so unreliable given our reliance on the tool.
One thing I was stumped with, is that a fresh install of home assistant is on
http://homassistant.local:8123 and it seemed restore of the backup did not work
The issue here was that my backed up config was from a system using
https://homassistant.local:8123 so it never came back finishing the backup
So change http to https after nothing seems to be happening anymore (wait approx an hour) and you may find your system is restored!
Just my two cents - suffering from the same issue - connected a monitor + keyboard - typing:
“core logs” - enter
(command prompt)
I see the logs are indeed changing, as if progress is made.
I had the same concerns today when I was restoring the backup. Not because it took so long but because during the process the onboarding page became unavailable. Was thinking something went wrong during restore but checking in console supervisor logs showed it’s actually doing something. Anyway my backup is 1.4GB and it took around 30-40 minutes to restore. Seems like old laptop (Lenovo T420i) with small SSD drive is thousand times faster than all this Raspberry devices. Not mentioning a lot cheaper 
I took mine actually free from my company but even if you want to buy such it would be around $50.
This statement is certainly not correct!
Raspi 5 with NVMe is not 1000 times slower, rather faster than your system
HA in Docker, importing a backup takes less than 2-3 minutes
Unpack the backup and copy it to the right place, done
It’s not only the host’s or ssd speed.
The time to restore a backup depends also on the amount of addons and the available internet download speed.
The backup contains only the addons-data, the addons themselves are downloaded from the internet.
At least if you restore the backup directly on a fresh installation.
Honestly I did restore today because I was switching from HDD to SSD. And even on HDD this restore took same time. But on SSD long period graphs (one year for example) generate much faster.
Wouldn’t it be better to clone the HDD to the SSD without importing the HA backup?
Wasn’t possible because HDD was 256GB and SSD 128GB and no tool was able to shrink partition.
Also it was just cleaner installation.