Thank you! this fix my problem everytime it went missing from devices….

seriously a big flaw from Razer...

This… Thiss… THIS… actually worked… Thank youu.

I finally got it. Leaving it unplugged for 30 minutes, then doing the button pressing + simultaneous power cord plugging worked for me. Thank you to everyone who chimed in. It seems there are myriad solutions to this issue, so don’t be afraid to try them all. 

If the button stays green, it means the operation was done incorrectly!! I don't have Bluetooth either. The light just gives an indication during the reboot process. Don't hesitate to try the operation several times, even for more than 30 seconds. Pressing the power button multiple times while the device is not plugged in is meant to discharge the capacitors inside the electronic components. This part of the process is really very important!!

Add as many details as possible, by providing details you’ll make it easier for others to reply

I’m unfortunately having this issue, too. Leviathan V2 with Subwoofer. I don’t have bluetooth on my PC so I am relying on the USB-C connection. I unplugged my whole rig recently to move it for some home reno work, and upon setting everything back up, the Leviathan is DOA. I tried the fast-pressing the power button to no avail. Every time I plug it back in, I get a green source button, but it does not switch to blue when I press it after the discharge.  I’d really prefer not to toss the whole thing in the trash, it was working perfectly fine before this. 

I did attempt to connect it via bluetooth with another device, and no dice. It appears in my bluetooth menu and “connects” but no I get no sound and it doesn’t show up in Synapse on either machine. Any other thoughts? Do I have a door stop? 

A MESSAGE THAT WRITES TO ME TO BE PINNED. worked every time I had the problem !

if anyone comes on this forum and has this issue now:

from what i can tell, you should plug these directly into walls, not a power strip. and that a power loss will result in a hard reset being perfomed. 

remove power from sound bar, hold power +/- for >10 seconds. you should see the sounbar apear in your bluetooth. 

source: 

https://www.reddit.com/r/razer/comments/174so56/leviathan_v2_with_sub_not_being_detected/

I fixed it by the following steps:

1. download SYNAPSE.
2. Turn off the speaker.
3. Hold the Blurtooth button until it turned on, and the source button “the left side button” will show up in red color if connect to bluetooth or green color if connected to PC.
4. Now play any sound, and you will found it only the Subwofer works.
5. Now unplug the power to switch off the speaker, and plug in the wire and turn speaker on.
6. Now you will find it works!

• Hi guys!
  
  I’m also have the same problem but i manage to fix this issue. Hope with these step will help you guys.
  
  - Plug all the cable, power cord like normal and press power button to turn the speaker on.
  - Then you gonna unplug the power cord.
  - Press and hold volume + ; volume - ; Bluetooth icon as the same time for 3-6 second
  - Plug power cord again and press power button. ( Windows should be connect Leviathan V2 normally again )
  
  If Windows doesn’t detect or Leviathan V2 not play any sounds. Try update the latest firmware for Leviathan V2 following this link from Razer support website: https://mysupport.razer.com/app/answers/detail/a_id/6274
  After you finish updating, restart your PC and Leviathan V2.
   

Tardy to the party and I found a fix on youtube that I didn’t think was going to work, BUT IT DID. I was having the same problems, power was on, but no connection to PC and couldn’t change the source. I unplugged this soundbar to install new PC mounts, so I knew it was this speaker being annoying and not any damages. All I had to do was unplug the power, THEN hold down the bluetooth icon and the volume up and down buttons. I had doubts this was actually how to reset this soundbar, but it worked!  I also initially tried holding the source button instead of the actual bluetooth button. Shows how often I actually try and swap devices with this annoying soundbar that shouldn’t be this wonky. Hope this helps someone

Sorry if I’m late to the thread. There is a solution for this and it works for me every time.

The sound bar needs to be electrically discharged after a sudden power surge or interruption. Just like some computer towers/cases. Do the following:

1. Unplug all cables from the sound bar. This includes all three: the power cable, USB-C and sub-woofer.
2. In the sound bar, press the power button quickly and repeatedly many times for 20-30 seconds. Don’t stop pressing the power button very quickly and repeatedly, and do it for at least 20-30 seconds.
3. Reconnect only the power cable. Press the power button in the sound bar. The sound bar will in PC mode (green source button).
4. Press the source button. If it switches to BLUE (bluetooth), then the issue is resolved. Connect the USB-C and sub-woofer cables and use the sound bar normally.
5. If the source button does not change to blue, the issue is not yet resolved. Disconnect the power cable and repeatedly press the power button many times for 20-30 seconds again.

This has been tried and tested and it always works. I hope it helps someone.

I've tried all the methods but still can't detect it.

help me!

this fixed my problem:

This is very disappointing, a speaker whose worth a merely 200 bucks is worthless, no solutions no luck! hey help us out here, your product sucks!

Thank you for the advice that helped. Certainly I am going to do all that do not respond to them connected via USB-C or via Bluetooth to proceed in this way. 

Holy Shit that worked. Storms and power surges always mess up the sound bar for days. AMAZING !!! Thanks, guys !!! 

it didn't work the first time. Then I unplugged the usb and repeated all the steps. After connecting the usb, windows and synaps detected the device. Thanks!

My guy you are a legend, I’ve had this problem for over a year now and this is exactly the method to fix it.

Lost count of how many times this has happened to me. Here I am again, bricked bar after power outages due to storm. 

Tried the usual firmware updater process:

Firmware Updaters

Razer Leviathan V2 Firmware Updater | RZ05-03920

Above didn’t work for me this time. What worked was doing a hard reset.

Follow these steps:

1. Pull out the power cable
2. Hold down the Power button, Volume Up and Volume Down
3. While holding down, plug back the power cable
4. Release the buttons after 3 seconds
5. Hold Power button, Volume Up and Volume Down again for 10 seconds

Hope it works for you

Cheers!

+1 to those who say that you need to disconnect it from the power, then try again.

fwiw, I disconnected for 1 hour before reconnecting. Windows now recognises the speaker again.

But yeah, for a premium product it’s really not very satisfactory. Razer, you need to learn from this.

i managed to get mine to be able to register with the pc again but it has no sound now, I've check and it responds to the chroma lights and volume buttons interacted but no sound still.

I have the same issue after tuned off my PC. every time that i make my PC start up this issue happen every time  synapse cannot detect soundbar. i had to disconnect cable and reconnect it to solve this problem.
lasted Driver of synapse and soundbar firmware updated everything.
hey Razer your product is suck. ashamed on you Razer.

no more buy your product.

I have the same issue after a power surge.

My Pc Windows or synapse doesnt detect the soundbar.

Bluetooth mode connects to my laptop but no sound.

Here is how i managed to start it again.

Remove all cables from the sound bar.

Remove the adapter from power socket. (This may not be necessary, just my experience)

Wait disconnected with no power about 15 minutes. (This may not be necessary, just my experience)

Press and hold power button for about 5 seconds. You should hear a low click inside the soundbar.

Connect every cable and power up.

I had the exact same issue, but changing power adaptors didn't work or only temporarily worked. In the end I pulled the entire thing apart, looked at everything, put it all back together and it's now working perfectly fine...

helped solve the problem by disconnecting the speaker from the power supply at night + resetting the settings (hold down the power button and -/+ volume)