After the 1/31 upgrade Zwift has been basically unusable on my MacBook High Sierra 10.13.3. On the 31st, I was able to start the workout, it froze, hopped around, there were random parts of bikes tiling in and out of the picture. To the point that the ride timer was 12 minutes shorter than the workout.
When the ride completed, I wasn’t able to get the menu button to come up to save and upload the ride. I wound up powering off the laptop and manually uploading the ride.
Today, I could notice as soon as it launched it was lagging. I wasn’t even able to get it to log in. I wound up aborting and completing the ride on the iPhone app.
Tonight I tried to re-download the Mac version and see if that improved anything and so far I’ve seen no difference.