Sensors freeze mid-ride; started after latest update

I have a Wahoo Kickr (gen. 2) with Garmin Ant+ speed/cadence sensors. After the latest update, I've had the sensors freeze mid-ride, although the app/video keeps running and can be paused. The sensors are just stuck at whatever value they were when the freezing starts...they just flatline on the graph.

My firmware and everything else is up to date; running Windows 10 Home on Dell XPS 15. I've never had this issue prior to the last update and no issues with Zwift at all.

Please advise, as this is a show-stopper. Stability is paramount...






  • Hi Andrew,


    I am sorry to see that you have had troubles.  This is not something that I have seen on version 5.5 (the most current at this time).  Let's try the following though:


    Pre-Workout - Ride Check Screen

    1. Click on each icon on the Ride Check screen and click the small 'x' next to each sensor that is listed in the submenus for each of those icons
    2. Once they are all disconnected, click on those icons again and re-select the appropriate sensor from the list and hit continue
    3. Start the workout once all of your sensors are connected again


    In Workout - Video Player Screen

    1. Once the workout has loaded and is started up pause it
    2. In the top right corner of the screen you will see the sensor connection menu icon; please click that (If you are unsure where that is you can see it labeled in this help article)
    3. Below your trainer's name you will see a drop box that most likely says 'Erg.' Click that and select on of the 'Level' modes and then switch back to 'Erg'
    4. Resume the workout and see if things start behaving a bit better


    Hopefully this sorts things out but please do let me know how things go either way.

  • Hi Cody,

    I pretty much do everything above all the time...switching back and forth between Level and ERG mode is a common occurrence, as I ensure that ERG is showing 50w before I begin and sometimes it's needed again mid-ride if there are a lot of intervals.

    I've never had this issue previously and all of my equipment has stayed the same. The only things that change are the firmware versions for the Kickr and TheSufferfest updates.

    The only thing that resolves the frozen sensors is to restart the app or to use the clear cache and relaunch function. Unfortunately, I lose the whole ride file when this happens.


  • Hey Drew,


    Can you please confirm which version of The Sufferfest app that you are using?

  • Version: 5.5.0

  • Ditto for me (Windows 10, Tacx Neo, App version 5.5).  Heart rate sensor input is also frozen (Garmin Ant+)

    Happening intermitently, about once every 3 or 4 workouts only

    Lucky today was on the last interval of a very dark place.  The bonus was I had to hold 270 watts over the cooldown period.  Clearly a minion trick!

    But seriously annoying when mid workout and having to restart.

    Otherwise absolutely brilliant App!

  • I am trying to dig into what could be happening here, guys.  I know that this is super frustrating and I am sorry for that.  Please do make sure that you check out this help article and see if any of these suggestions help.

  • Thanks for chiming in Tony...I concur with the issue being intermittent. Anecdotally, I would say that it occurs when I've done a video that's over an hour or if I'm doing videos back to back, on the second video. Maybe an app cache issue?

    Cody, I have a hard time believing it is a sensor issue when the app is not "losing" connection to my Ant+ sensors (Kickr, Cadence, Speed), but freezing the values of each for the rest of the video duration. I can disconnect/reconnect multiple times and the sensors are found, but the values are "stuck".

    I did The Chores last night without an issue...ISLAGIATT had the issue last week with 10mins to go. I'll continue to provide feedback if anything else comes up, but I'm hoping that a future update could make this anomaly go away.

    Thanks for your help guys!


  • I can't say that I disagree Drew but I have to start simple and work up in my world.  ;)  With that said we are working on further solidifying sensor connections, especially Ant+ with the next update.

  • Thanks Cody, looking forward to v.6 update coming soon...


    ...having said that, this past weekend, I completed a 2 hour Endurance session (Open:60 extended) and Blender without an issue. Go figure!





  • That is some good news at least, Drew!

  • I am having the exact same problems with my Tacx Vortex data freezing up while the video continues to play.  Looking forward to any help too.

  • As I mentioned before we are working on our ant+ connections with the next update.  Something that you can all try if you are using the desktop app is to go to Help>Clear Cache and Restart in the top menu.  This may help a bit for now.

  • Understood clearly that you’re working on the Ant+ update.   Ignore the email that I’ve just sent but did want to record that I’m having the same issue. 

    I’ve switched to my Cyclops Fliud 2 from the Neo as a test before I discovered this thread and had the same results.  Using all Garmin sensors  

    The only difference for me is I have to do a hard reset of the pc each time the freeze occurs. 

    I’ll switch to the Viiiiva HRM tomorrow via Bluetooth-Ant+ bridge and see if I can make it through the full video. 

    Brilliant program, btw. 

  • Just another one for feedback along the same lines (like there wasn't enough :) ) :

    I have similar 'freezing' issues but for me they all happen (so far) ONLY when I get my laptop connected to a computer monitor screen (via an HDMI cable):

    1. while playing the video, every 2 min or so, the video and everything except the timer are freezing for a half a second or so and when they restart it is from 1 sec or so back. Not sure I got the description right... I guess similar to short freeze followed by a re-play from 1 sec before the freeze. This is one of the symptoms.

    2. The second issue is, similar with above from the thread, the entire video skips ahead by a random number of minutes. See attached Image_1 and Image_2.  And also, along the same lines, at the end of the workout the sensors were all frozen but the video kept going like nothing happened, while I was completely stopped and watching the screen (good thing was during the cool down). See Image_3 attached (or below).  Also during the ride the 3 sensors showed 'frozen' periods, but they came back in 10-20 seconds - I just ignore them and kept riding. This one seems to me a 'display' issue, as the app continued recording what appear to be the right values, just not updating the screen fields (judging by looking at the log after the ride).

    My setup: App Version 5.5.0, Win 7 on Dell Latitude 15 5000, Garmin USB stick for ANT connection, with Garmin HR, Wahoo cadence, and Wahoo Kickr Core.

    Looking forward for the new version. Great system otherwise!


  • Thanks for this guys.  We are hard at work on this one.  One thing to mention, dGiovani, is that Windows 7 is below what we recommend in our minimum requirements.  I understand though that this is still an issue and as I mentioned we are working hard to get it fixed up.


    If this issue is plaguing you to the point where you can't get your workouts in drop me an email at

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