Sense 2 not coming on

[Chychy]

• I just picked up sense 2 from Argos. And it's not coming on. 
• There's a big red X
• The screen hasn't come on
• Really frustrating

[Talahthas]

Welcome to the Fitbit community, @Chychy!

Sad to hear that your Sense 2 isn't working as expected.

Was your device factory sealed when you've purchased it? If it wasn't, I'd suggest getting a replacement.

Otherwise I'd recommend doing a factory reset on your Sense 2 to hopefully get things fixed. In order to do so, please keep your device's button pressed for around 10 seconds until you'll see the Fitbit logo flashing on it's display. Then release the button and immediately keep pressing it again until there's a circle around the Fitbit logo. Now release the button and wait until your device has restarted.
Finally, please follow the instructions provided here to set up your device:

How do I get started with Fitbit Sense 2?

[Rge]

When booting up, the Sense 2 will get to the red X, stays for a little bit, the shows the blue diamond and then boots up. 
Just have to wait for it.

Don’t know if this is your issue, but it took me a few tries to figure that out.

[SunsetRunner]

Worked like a charm!