I'm migrating from ST, and in the process of adding my very last ST ZigBee plug in outlet to HE C-7 and the web interface froze. Bottom left of Chrome stated: Waiting for [HUB IP]. I let it sit for awhile with no luck. I refreshed the page and it left me with a white screen with the same "waiting message" on the bottom. I tried Edge and IE with no luck. I ended up unplugging the hub and it started with the normal boot screen. I logged in successfully then after about a minute it froze again not letting me do anything, showing the message from Chrome "waiting for [HUB ip]. It does this every time I plug and unplug, I get about a minute to do anything once logged in (everything seems to work in that minute: lights/switches turn on/off, dashboard works, I can open devices and see them)... but after a minute it freezes. I've tried the diagnostic tool, but when I enter my mac address to reboot it says "invalid password." I've tried, with ":" "-" "." and with no symbols.
I read about a potential issue with RM if a Rule was created incorrectly. I deleted the RM APP in hopes it would help, but it didn't. I was able to role back a version in the diagnostic. I had installed the latest version over the weekend... so after the role back I'm sitting currently with the version prior.
I did save off a back up copy to my PC on Saturday, but I can't seem to get to "soft reset" to roll it back.
I emailed support, but thought someone here might have run into this issue and solved it.
Light on the unit starts blue and turns green. It seems that once the light turns green It freezes.
I would reboot it into safe mode. If it locks up then, it almost has to be a hardware issue (in which case you would then pursue a return with support).
If it doesn't, then it could be a number of things.... Hub code bug, app bug, driver bug, device bug, overheating hub.
That’s a VERY severe approach, you may (probably) have a corrupted database; not good to pull the plug, but you may not have had a choice. Two things to try:
(1) because you seem to be able to get into the hub, try creating a backup, download to your computer, restore that backup. Or,
(2) you could restore a prior backup (saved on the Hub every night at 2:00 am), but that could lose work done since the last backup.
On rereading, it seems you could have a hardware issue, but you could try going back to your earliest nightly backup first, just to see. Then perhaps you could restore forward to a later backup.
I can, but it asks for a password (MAC address) when I try to reboot/shutdown/safe mode.... I'm entering the one from the back of the hub and it says it's wrong.
Your first guess is likely the problem Based on details provided and our preliminary research, this is a typical case of corrupted database. Safe Mode to disable custom code, then Soft Reset to recover the database should fix the problem. @brackneys , please see my PM for more details.
I had tried restoring a few times from Saturday's save point, but couldn't do it fast enough before it would freeze again. This last time worked though and I'm back in! Thanks everyone for your help.
Based on details provided and our preliminary research, this is a typical case of corrupted database. Safe Mode to disable custom code, then Soft Reset to recover the database should fix the problem. 
