Stuck in boot loop / Triangle of Death

In my comment in reply to Lumik0 click in and view parent replay I follow his instructions and everything ok

I have tried exactly that. Doesn't work for my descent Mk3I

Actually I think is not necessary to STOP the watch since it is in a boot loop... Just wait the triangle to appear and then press and hold START/STOP until it connect with Garmin Express...

These steps will require the following to complete:

Access to a personal computer Windows or Mac.
You will also need to install Garmin Express to your computer.
Power/data cable for your watch.
Your Garmin Connect credentials
Open Garmin Express on your computer.

Connect Descent Mk3i to computer.

Wait for the watch to reboot and immediately press and hold the start/stop key when you see the blue triangle.

Continue to hold the start/stop button for 10 seconds then release the button.

Wait 30 seconds for Garmin Express to find the device. Once the watch is recognized, complete the process of adding the device. This will include signing in using your Garmin Connect credentials.

The watch should complete a sync with Garmin Express. Once the sync is complete, you can disconnect the watch from the computer. The watch should boot up normally.

Or delete the file as Jean said

Tested on windows PC

Don't worry about the light button.

1-Connect the watch to the PC

2-launch Garmin Express synchronization

3-press the start button several times (top right) for a few seconds until the rise is detected

4-remove corrupted file

this method worked for me and

the watch has not been reset

Works on a Mac too.

connect watch via original usb-c to the mac

On Garmin Express select add new device

press and hold the Start/Stop Button (after a few tries the triangle keeps permeant)

in express you can abort to add a new device

your watch finally sync again

After that my watch was factory reset and you have to new add it to the connect app

when you finished you can select a backup to be installed, and everything is like before the crash

hope this helps 

I had the same blue screen since yesterday, tried the solutions posted but still wasnt booting. Garmin Express was picking up the device and showing its connected but still I just had the blue triangle.

Express also showed a maps update which I tried to install but it didnt do anything despite going through the process completely.

Lots of fiddling later and its hard to say exactly but I think it involved double tapping the light button while connected to the PC and suddenly I got boot screen and it followed setup like its been reset. Lucky it picks up its backup and restored that too so back to normal..

So glad to have it back up but am also seriously concerned that Garmin can so easily brick such a pricy gadget!

I have the same probelm and went through exactly the same process in the last 24h with no results.

Somebody please help me?

I managed to stop the boot loop by pressing Start and connect the watch to Garmin Express but still cannot have it appear in the file explorer :/ Tried reverting to a backup from three days ago within Express but it did not help. Anybody had such issue? The PC must be recognizing the watch since Express is able to connect but I just can't browse the files :(

EDIT: In the end I just factory reset the watch... Turned out it was quite a fast process, the backup from two days ago got applied in like a minute or so, so all in all I recommend everyone having trouble with the watch showing files on PC to just factory reset if you have a backup (I think you can check it in Garmin Connect and/or express). Way more efficient than fighting with the boot loop and praying the PC finally catches on :D

It's OK for me.

Thx