Why would I see this “Failed to setup” error running Z-Wave JS add-on when all devices are working properly?
I’m not running the Z-wave JS UI add-on at this point but have in the past. When running that add-on and not running the JS add-on there were times when the JS-UI add-on would update and I would see this issue and devices were not working.
Today it appears we no longer need the JS UI add-on to take advantage of LR.
have tried a power cycle of your HA box ?
Multiple times. I’ve tried everything any of the ai models have suggested.
First look at the HA logs for the exact error that is causing the failure. Then look at the add-on logs if it is failing.
I ran into a similar issue a couple of days ago.
-HA OS virtually on UTM with two USB devices mounted on startup
- ZooZ : 800 Z-wave stick, firmware 1.5
- Insteon Modem : FT 232R USB UART
I have occasionally run into issues when restarting the VM, where the USB devices do not mount, but a couple of full and safe restarts would correct the issue. I place this issue with the UTM app and startup sequence, not with HA.
After updating
- HA OS 15.0 → 15.1
- HA Core 2025.6.3 → 2025.7
I received the same error ‘failed to setup’ z-wave after every restart.
I investigated. The first oddity I found was the /dev/serial folder was no longer there. A serious problem from my perspective since the integrations refer to these ‘aliases’ ( for lack of a better word) as shown in the log files.
Digging further, I then found the Z-Wave USB device on the VM was being named something different from the past. It used to be descriptive and simple ‘800 Z-Wave Stick’ and now it was being named something like ‘Device-blah-something2:’ ( I did not record what it was) . This was preventing my startup script from mounting the Z-wave USB auto-mount on startup due to the hard coded name in my scripting.
I attempted to reconfigure the current controller ( Z-Wave) and select the ‘newly named’ USB device within the Zwave integration AND the Zwave JS add-on. It would not work and the ZWave USB device would not connect.
I reverted both HA OS & Core and am now operational.
Posted too early regarding reversion. Same issues happening with earlier versions of HA Core and OS.
It seems the Zooz Z-wave stick flaking out. Name changes and unmounting on it’s own. I have no issues with the Insteon Modem and moving devices around on various USB ports yields the same flakiness with the Zooz Z-wave stick.
After a few iterations of various version installs of HA Core, HA OS and Z-Wave JS. I finally have a stable setup. Had to roll back to Z-Wave JS v.0.15
my config
Mac OS 15.5
UTM 4.6.5
HA OS 15.2
HA Core 2025.7.1
Z-Wave JS 0.15 (0.16 & 0.17 were not able to maintain a steady USB connect with the Z-Wave USB stick)
ZST39 LR by Zooz Firmware: 1.50
The issue turned out to be some sort of corruption with my Z-Wave JS install / config files. I did not find any other online reports of issues with Z-Wave JS and versioning and the system flaked out every time when starting Z-Wave JS addon.
I have 22 Z-Wave devices. I disabled and uninstalled (with all data deletion) Z-Wave JS from HA, both integration and add on. Restarted HA and VM a couple of times.
Reinstalled Z-Wave JS and got a stable system. I had to factory reset five devices, but did not have to recreate from scratch, since the z-wave devices were recreated in HA.
The issue turned out to be some sort of corruption with my Z-Wave JS install / config files. I did not find any other reports of issues with Z-Wave JS and the system flaked out every time when starting Z-Wave JS addon.
I have 22 Z-Wave devices. I disabled and uninstalled the Z-Wave JS from HA, both integration and add on. Restarted HA and VM a couple of times.
Reinstalled Z-Wave JS and got a stable system. I had to factory reset five devices.
My Z-wave integration continued to be unstable and I replaced the Z-wave Stick with a new 800 Z-Wave USB STick ZST39 LR, Firmware 1.6
Have had no problems after the Z-Wave stick replacement.
Was facing a similar issue but for me was that I had forgotten that the UTM window had to be in scope when plugging in the Z-Wave USB stick.
