Ever since around the same time as the most recent Smartthings update (around April 9), my system (Samsung SmartThings Hub v3 2018 - with many zigbee and z-wave devices) has been unbelievably and excruciatingly crappy. For the first few days, the hub was dropping offline approximately every 2 minutes and coming back online several minutes later. So probably up and down several HUNDRED times in a day. Now its down to offline just a few times each day. Also all of my virtual switches are failing that are supposed to auto revert. Any time I trigger a motion sensor to turn on a light, I am sitting in the dark for at least 5 minutes before it finally does something. If I have to manually turn off a smart plug in the app it will continuously show its loading and never do anything EVER. I don’t know what’s up, but to me this is completely unacceptable. I have had to reboot the hub many times and it sometimes fixes it for a day, then I am soon back to where I was before. Looking to see if any one has had similar experiences and any advice! Home Assistant is looking pretty attractive right about now.
How is your hub connected? WiFi or Ethernet?
Login here:
Choose one of your virtual switches and post a screenshot from the complete Summary section.
If I was you I would try rebooting my house, power off from the main power switch and power on again.
Hub is connected by ethernet directly into the router. It is plugged into a surge protected UPS.
Here are the screenshots.
Reboot a house? Lol. I put the hub on a wifi smart plug because I have to restart it so frequently.
Just wanted to make sure that your virtual switches are locally executed.
So just rebooting the Hub may not be enough. Check out this approach and follow the steps for a “methodical” power-cycle of the house (which should be kinder to various electrical components than an abrupt Main Breaker Off/On) 
The “reboot the whole house“ approach often causes more problems than it fixes if you are using matter devices. 
They just don’t work well unless everything comes online in a specific sequence.
See the following article:
https://www.derekseaman.com/2024/09/essential-tips-for-a-stable-matter-over-thread-network.html
Hi, @Docga
Can you enable support access to your account, please?
Also, can you confirm the following, please?
- You haven’t changed anything in your network recently
- When the Hub becomes offline, which LED color do you see?
To provide support access, please follow the steps described here:
- Confirm the email account registered in the forum is the same one you use for SmartThings. If not, please share it with me over DM
- Enable support access to your account:
- Go to the SmartThings Web (my.smartthings.com)
- Log in to your Samsung Account
- Select Menu (â‹®) and choose Settings
- Toggle on Account Data Access
- Select the time period and confirm - In this step, please select “Until turned off”, once the team finishes, we’ll let you know so you can disable it again.
I have messaged you my account information and enabled support access. Hopefully you can rescue my system! I have not changed anything with my network at all recently. Everything was working pretty well before until now. I haven’t had the chance to see what color the light shows because it is in the basement where I am not normally located. Let me know if you are able to pinpoint anything.
Hi, @Docga
I created a report for your case to see if the team can search the hub logs for the cause of the restart.
However, while I was checking your Hub’s info, I saw it went offline a few times and noticed it has the memory properties at “hard limit”.
This means the Hub is running out of resources, and we’ve seen the Hub stopping certain services to free up some memory or sometimes, rebooting itself.
For now, my suggestion would be for you to check which drivers you’re using and if you can reduce their number, for example, instead of having a separate driver for each light device, see if a single one can control all of them.
Also, if the driver has many custom functionalities, its size will be bigger and thus consume more memory.