@Kevin_Z 

Hello and thanks for the reply -- Here are some answers to your questions -- 

1. When the router restarts, are all the LEDs turn off then on automatically and the internet on it will temporarily down then recover? How long does this process take?

I have yet to "catch it in the act", I can only see the messages in the log that it is rebooting and that my NVR and t-stat go offline. I can't gauge the time it takes being I am typically not watching it during the reboot cycle it does.

2. May I have your network layout, how is the C4000 connected to your network? Are there any other range extenders or switch in the network? If yes, try to remove it first and confirm again.

I have the topology somewhat like this - wan -> cable modem -> c4000 -> From here i do have 2x 5 Port L2 switches.

3. Who is your ISP and what kind of modem are you using? Is it a Dynamic IP setup on the C4000 WAN or PPPoE?

Xfinity/Comcast is my provider. I have a Netgear CM700 modem and I believe my speed should be 300Mbps and setup with a Dynamic IP although I have my PC mac cloned.

4. How many devices are connected to C4000, wired, and wirelessly? What are they? Is there any new device connected to the C4000 network recently when the C4000 begins to reboot? Or did you upgrade the router firmware recently?

There is roughly 20 devices on my network. Hardwired -> 2x Dekstop PCs, Lexmark Printer, Samsung TV (hardwire), NAS, NVR, 1x POE Injector, PS5. Wireless -> T-stat, Samsung tablet, Chromebook, Android Phone, 2x iPhone, 2x Nintendo Switches, Samsung TV (wireless), Roku device, gargage opener, 1x smart plug and alexa device.

Most these items are static and don't change that often unless we are coming and going from our house. Firmware has not been updated since last release which I believe was over a year ago atleast.

5. Is there any other setting or feature in your network that may cause this restart issue, or is there any special operation/activity in your network that causes the C4000 to restart, such as high loading or real-time calls?

I am unsure on this, although the little guys do play fornite with eachother daily, although that has been going on for several months now. The reboot issue has really stemmed recently and happens roughly 1-2 times a week.

6. Is it the original power adapter on the C4000? Is the power stable in your house? How about other electrical devices in your house, are they stable?

Original power cord/wall wart. As far as I know, the power in my house is fine? I don't see anything else having power issues.

7. Try to reset the router to factory defaults and reconfigure it from scratch to confirm again.

Interesting. My settings haven't changed in a very long time. I guess it would be easy to try being mostly the device is "basic" config besides vpn and port forwarding.

@Kevin_Z 

Hi again.

Unfortunately I don't have a receipt and it has been well over 2 years now.

I bought it at Frys and that company is now "no longer".

I guess I am SOL?

I will still try the manual rebuild, but I won't hold my breath.

Thanks for the replies.