Altimeter negative spiking after 17.50 upgrade, causing gigantic errors

I was able to downgrade, but all settings, incuding sports screen customization are gone. 

If 16.50 brings back a reasonable elevation gain for me I'll never upgrade drivers again for as long as the Instinct lasts. Wish I would have stayed with 12 or so; that was perfect for me.

Harrywdid you save all the various *.fit files from your watch on your PC?
If yes, there may be still a chance to recover your personal settings. I read in the above mentioend device back-up instruction, that you need to put all the *.fit files in the "NewFiles" subfolder. Have you done this?

Ah, no. Thanks, I might try that at some point. But I have them mostly pieced together already - I took a good look before I downgraded.

Tengo el mismo problema fallo, altura real 600 m y el reloj marca 6000 o mas.

Another with altimeter problems after update. 1200m convert it to 19000m. Garming please fix this!!

Hi Garmin - Chris

I recorded a video where you can see how the bug is present. It's a simple road bicycle ride in a soft steady uphill. I recommend you play this youtube video at 0.5 speed (this option is available in the Youtube settings window) and look at the bottom field of my Instinct. You will see it bouncing from 8xx to 7xx, then 6xx, then again 8xx, that's spikes of hundreds of meters. It results in totally useless altitude profiles. With a saw like profiles (like posted in the my first post) demonstrating that this bug is present and resulting in those absurd accumulated climbs of 10,000+ meters.

By the way I tested with the altimeter set to milibar units as some user said, it made no difference.

Let me know if you need access to the activity or any other thing.

Please fix this as quickly as possible.

serjmac Have you tried to wear the watch on your right arm? I have the impression, that this helps at least a little bit to improve the readings (as the pressure port opening is not pointing in the driving direction, and thus not sensing extra "dynamic pressure").
And what I also would like to recommend to check: are the pressure sensor openings really clean and not clogged by remainders of sweat, sun cream, ...? Both of them need to be completely unblocked.I recently used a manual spray bottle, put the spray nozzle to "hard jet" mode and rinsed them really profoundly. This also helped to getter better readings - without these enormous spikes.

Perhaps you'll give these to measure a try (ideally on the same trip) and see, if your altitude measurement is "smoother" and the total ascent gain is more realistic.

Mi reloj es nuevo, antes de actualizar a las 17.50 iba perfecto. it's a software bug.