COROS watch problems and fixes: what owners report in 2026 and what COROS says to do.

By Raji Shah · Published 2026-10-19

COROS has a written fix for most watch problems, but 2026 brought one it didn't: watches, mostly the PACE 3, failing after a firmware update. This guide collects COROS's own fixes for the problems owners report most, from dead dials and battery drain to sync, GPS, and heart-rate errors, with counts of the owner reports on COROS's official subreddit and, where COROS has replied, what it said. It focuses on current models: PACE 3, PACE 4, PACE 4 Pro, PACE Pro, APEX 2, APEX 2 Pro, APEX 4, VERTIX 2 and 2S, and NOMAD.

Watch died or stopped responding after a firmware update

This is the problem that dominated 2026. On COROS's official subreddit, at least 20 owners described some mix of these symptoms after an update between February and October: a dial that turns but doesn't register, a dead touchscreen, battery draining from full in hours, and in the end no power. Separately, at least 40 owners, some of them among those 20, posted between June and October that their own watch was bricked, dead, or unresponsive. Most were PACE 3 owners, with APEX 2 Pro, APEX 2, PACE 4, and PACE Pro owners among them. These are minimum counts, and a failure after an update doesn't prove the update caused it.

COROS's account of it has shifted. In June 2026, its CEO said tickets after recent updates were higher than normal, but that the reports didn't show a widespread software problem, that more than 99.9% of updates complete successfully, and that updates may expose or accelerate hardware faults that already existed. On June 17, COROS's official account said support had answered more than 100 tickets in 72 hours and was offering free replacements, and that every case would be reviewed so watches that failed after an update get replaced. On October 14 it said the issue in "that specific update" had been identified and that later updates had not had problems, without naming the version. Owners still posted failures in October, and replacement outcomes varied: at least 4 out-of-warranty owners said they got free replacements in September and October, while others said they were offered 20% off or a paid repair.

1. Charge it properly for at least 2 hours from a computer or a 5V/1A adapter, not a fast charger, then unplug it and hold the power button for 15 seconds.
2. Don't reset it or reinstall the app if workouts haven't synced; photograph them in the watch's activity history first if you can.
3. Open a ticket in the app under Profile > Customer Support > Contact Support with the words "critical hardware failure," a photo or video of the screen, and the watch's 6-digit ID. COROS's official account said in October that tickets filed in the app let support read the watch's logs.
4. Ask about warranty and repair: COROS watches carry a 2-year warranty from activation, and its paid repair program covers battery, button, dial, and screen faults.

Firmware can't be rolled back, and COROS documents no computer updater. If your watch shows "Please connect to PC to upgrade firmware," see our guide to COROS update problems, which covers that screen and a safer update routine.

Dial or touchscreen not responding

If the dial or touchscreen stopped working after an update, see the section above first. If the dial won't scroll or press, or a button sticks, COROS's steps are to rinse the watch under warm running water for 30 to 60 seconds while turning the dial and pressing the buttons, let it dry completely, and restart it with the 15-second hold. If that doesn't help, reset it from the app under Profile > your watch > Remove, which works without the dial; sync first, because Remove can erase workouts that haven't synced. If none of that helps, the part may be damaged; contact support and say when it started and whether the watch took a knock. At least three owners said draining the battery to zero and then charging for about 2 hours brought a dead dial or touchscreen back for a while, but COROS hasn't endorsed that.

Battery draining fast

At least 35 owners posted about abnormal battery drain in 2026, at least 15 of them tying it to a recent update, with the PACE 3 named most. COROS lists its biggest battery drains in this order: vibrations and tones, the backlight, weak or lost GPS, the satellite mode, connected sensors or heart-rate broadcasting, built-in sensors, navigation, and the Daily Stress feature.

• Check the Battery Health page in the app (Profile > your watch > Battery Health), added in June 2026. It shows a week of use by feature and the estimated days and GPS hours left, and flags a critical hardware failure if the watch detects one.
• Turn down the biggest drains: vibrations and tones off, lower brightness, Always On off on the PACE 4 and PACE Pro, daily heart rate every 10 minutes, a lighter satellite mode, and Stress off.
• Calibrate the battery: charge 30 to 60 minutes past 100%, use the watch until it is below 10% or shuts off, charge it to 100% without interruption, then turn it off and on. COROS's official account said in October that faster drain is common while an update settles, and suggested running the watch below 10%, then charging it to 100%. If yours drains from full in hours, see the first section; some owners with that drain said charge cycles, restarts, and resets didn't help.

Watch won't charge or turn on

COROS acknowledged in August 2025 that the standard cable for watches with its A1 charging port can loosen with wear, so the watch charges on and off or not at all. That covers the PACE 2, PACE 3, APEX Pro, APEX 2, APEX 2 Pro, original APEX, and the VERTIX line. Its fixes are to rinse the port and cable pins in fresh water without soap and air-dry them for at least 30 minutes, try another power source, charge on a flat surface, gently pinch the connector with pliers or use COROS's A1-to-USB-C adapter, and send COROS a short video through its support form if nothing works. The PACE 4, PACE 4 Pro, PACE Pro, NOMAD, and APEX 4 use a snap-on adapter that takes any USB-C cable. COROS says to charge only from 5V/1A sources, never fast chargers or fast-charge power banks.

If the screen stays black, COROS's power-on steps are: plug in and hold the power button for 15 seconds; if that fails, rinse the watch and cable, dry them, and try another outlet; then charge for more than 2 hours, unplug, and hold the power button for over 15 seconds. The power button is BACK/LAP (lower right) on the PACE 3, PACE 4, PACE 4 Pro, PACE Pro, NOMAD, and APEX 4, and LIGHT (top right) on the APEX Pro, APEX 2, APEX 2 Pro, VERTIX 2, and VERTIX 2S.

Watch restarting by itself

COROS says a low battery is the most common cause of unexpected restarts. Its order of fixes is: charge the watch fully from a standard port, update the firmware and keep the watch connected while it installs, restart it with the 15-second hold, re-pair it, and then factory reset it. If it keeps restarting, tell support when it happens, how often, and which firmware version you run. In October 2026, at least two owners reported reboots after V3.2008.0: an APEX 4 that restarted three or four times, and a PACE 4 that restarted twice in one run. On October 8, COROS's official account said support was looking into the PACE 4 reboots.

App won't connect, pair, or sync

If you use an iPhone and the COROS app stopped working in September 2026, update it: COROS renewed its connection certificates on September 16, and says app versions older than V4.9.11 may be unable to open, connect, or sync. Android wasn't affected, and synced history is safe. Separately, on September 6, most of the 25 people posting in one thread on COROS's subreddit that day said the app wouldn't sync (the first poster got a "Network Error"), and at least four said it worked again later that day. At least 7 owners also reported connection drops or slow syncing between September 8 and October 11, on both iPhone and Android.

For workouts stuck on the watch, COROS's first rule is not to uninstall the app or reset the watch, since either can lose them. Then:

1. Keep the phone nearby with Bluetooth on, pull down in the app to sync, and wait up to 2 minutes.
2. Check that the watch shows as connected and that the app wasn't force-closed, then restart the phone and the watch.
3. Record and save a 1- to 2-minute test activity, which can push older ones through.
4. Update the app from the app store, without reinstalling it, and update the firmware.
5. If workouts are still missing, photograph them in the watch's activity history and send the photos to support, which can sync them by hand.

To pair again, turn the phone's Bluetooth off for 30 seconds, restart both devices, forget the watch in the phone's Bluetooth list, and remove it from the app. Removing a connected watch resets it, so sync first; to unpair it without wiping it, COROS says to turn the watch off (System > More Settings > Turn Off) before removing it. Then add it under Profile > Add New Device by scanning the QR code on the watch (System > Pair Phone), and confirm the pairing code on both devices if one appears. On Android, COROS also suggests excluding the app from battery optimization, checking its location and app permissions, and clearing its storage.

Activities not reaching Strava

Activities go from the watch to COROS's servers and then to Strava, usually within a few minutes. When they don't, COROS's steps are to check the Strava and COROS status pages, disconnect Strava under Profile > Settings > 3rd Party Apps, force-close the COROS app, clear the phone browser's cookies, restart the phone, and reconnect with any VPN off. Activities that failed before you reconnected won't sync by themselves: export the .FIT file from the app (the activity > three dots > Export Data) and upload it to Strava by hand. Between late June and early September, the only day with a cluster of Strava reports was August 5, when at least 15 owners reported missing uploads and COROS's official account said the same day that its Strava sync data recovery was complete. COROS's status page, last updated in March 2025, doesn't mention it.

GPS, distance, and treadmill errors

COROS says its GPS is accurate to about 3 meters with a strong signal, and that trees, tall buildings, and water distort tracks. Its fixes:

• Wait for a solid satellite icon, then about another minute, before you start.
• Pick the right mode: All Systems On for most runs, and Dual-Frequency in cities, canyons, or forest on the models that have it (PACE 3, PACE 4, PACE 4 Pro, PACE Pro, NOMAD, APEX 2 Pro, APEX 4, VERTIX 2, and VERTIX 2S).
• Keep satellite data current. The app sends 7 days of satellite data whenever the watch connects; after a longer gap, a first fix can take 2 minutes or more, so update it under Profile > Satellite Data.
• Fix the distance afterward. In the app, open the activity, tap the three dots, and choose Edit > Distance; average pace recalculates. For indoor runs of at least 1 km without a set speed or structured workout, the watch asks you to confirm the distance, and doing so updates the stride model it uses on the treadmill.

If you see "AGPS verification failed," COROS says to turn off any VPN, switch between Wi-Fi and cellular data, and clear Safari's history, then restart and reset the watch if it persists. In October, COROS's official account answered two owners whose treadmill distance was off: about 15% long on a PACE Pro, and 13 km for 15 km on an APEX 4. It told both to confirm the correct distance after each run so the watch learns their stride, or to enter the treadmill's speed.

Heart rate looks wrong

COROS lists wrist temperature, a loose band, sweat or water, the watch's position, tattoos, skin color, and hair as things that throw off optical heart rate, and says chest straps usually give better accuracy. Its fixes are to wear the watch snug above the wrist bone, keep your hands warm, move it off a tattooed wrist, wait on the start screen for a stable reading, use Interval Training mode for intervals, and clean the sensor without alcohol. For cadence lock, where the sensor reads your arm swing instead of your pulse, COROS suggests a snug nylon band or a chest or arm strap paired over ANT+ or Bluetooth; our optical heart-rate guide explains why wrist sensors struggle.

Separately, at least 5 PACE 3 owners reported heart-rate problems between September 8 and October 16, 2026, including all-day heart rate that records only during workouts, which leaves no sleep data. On October 16, COROS's official account told one of them to contact support again so support could check the watch's logs, and no fix had been announced as of mid-October. By default, COROS measures daily heart rate every 10 minutes; the same day, its account told an owner whose daily readings looked wrong to set standby heart rate to real time, though COROS's battery tips recommend the 10-minute setting.

Notifications not arriving

In the app, turn on each app under Profile > your watch > Notifications, including Other for apps that aren't listed, and on the watch turn on message and call alerts and turn off Do Not Disturb. On an iPhone, also turn on Share System Notifications for the watch in Bluetooth settings, set Show Previews to Always, and allow COROS through any Focus mode. On Android, give the app notification access, phone, SMS, and contacts permissions, and unrestricted battery use. If alerts still don't arrive, force-close the app, toggle Bluetooth, restart both devices, and re-pair. COROS also notes that vibrations and tones switch off automatically below 0°C (32°F), and that notifications appear on screen only while you're wearing the watch.

Sleep or HRV data looks wrong

On current COROS watches, the first sleep of the day longer than 3 hours gets a full sleep score and stages, and any other sleep counts as a nap. COROS's fixes are to wear the watch snug at least 2 cm above the wrist bone, set your sleep and wake times in 24-hour format under Profile > Settings > Sleep Settings, and edit, merge, or restore a sleep log on the app's sleep page. Overnight HRV needs 5 nights of wear to set a baseline and comes only from the watch's own sensor; COROS doesn't take HRV from chest straps. If a PACE 3 records no sleep at all, see the heart-rate section above. Our HRV guide for runners covers how to read the trend.

Update failed or stuck

You install COROS firmware from the app (Profile > Update Now, or your watch > Firmware Version) in one of three ways: Bluetooth, which works on every model but is slowest; Wi-Fi, on some models and only over 2.4 GHz networks; or Direct Transfer, the fastest, on some models. Wi-Fi models can also update from the watch itself under System > WiFi > Firmware Update. You can't downgrade firmware or choose which features to install, and older watches eventually run out of storage for updates: COROS said in 2024 that the PACE 2, APEX Pro, and original VERTIX would get no more firmware updates. When an APEX 4 owner's Wi-Fi update froze at 9% in August 2026, COROS's official account said that was not a critical hardware failure and suggested a different 2.4 GHz network and a phone restart; the owner said that after a restart, the watch was back on its previous firmware. If an update leaves the watch unable to start, see our COROS update problems guide.

Restart or factory reset: which to use

COROS's rule for both resets: sync first, and never reset the watch or reinstall the app while workouts are still on the watch only. A restart keeps your data.

Contacting COROS, warranty, and repair

COROS recommends a ticket in the app: Profile > Customer Support > Contact Support, choose the model and topic, describe the problem, and attach photos or video; if no confirmation email arrives within 24 hours, submit it again. The other routes are a web form on its help center and an in-app chat assistant that doesn't hand off to a person. COROS has no phone support. Include the watch's serial number and 6-digit device ID, both printed on the watch and shown under Profile > your watch > About in the app.

COROS watches have a 2-year warranty from activation, handled in the country of purchase. Outside warranty, COROS's repair service, offered in the US and listed EU countries, exchanges a watch with a battery, button, dial, or screen fault for a "like new" unit with a 1-year warranty, for $59 to $119 in the US as of October 2026; it takes about 5 to 10 business days, and each watch can use it once.

Bottom line

Most COROS problems have a documented fix, and the first steps are usually the same: a 15-second restart, a charge from a 5V/1A source, an app and firmware update, and COROS's sync and pairing steps. The exception is a watch that dies after an update, which owners kept reporting through October 2026; there, charge it and try the 15-second restart, don't reset it while workouts are unsynced, and open an in-app ticket with "critical hardware failure" in it. Before your next update, read our COROS update guide, and to judge whether a GPS track or distance is really off, see the GPS accuracy guide.

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