Update: This issue should be fixed for most users now. Please update to the latest game version.
There's currently an issue where Mac computers below Zwift's minimum requirements will freeze or stutter (low Frames Per Second) when the program is open. This affects computers attempting to open Zwift on the Intel HD 3000 graphics chipset. We are investigating to see if this can be fixed.
If you have a computer with a discrete (separate) GPU that you can switch to instead of using the integrated Intel HD 3000 graphics, you may be able to get a better framerate. Alternatively, you could use a computer or device that meets Zwift requirements for a supported experience.
All computers experiencing this issue are below Zwift's minimum requirements and likely around 6-7 years old in terms of their manufacturing lifecycle (very old in computer terms). If you've been thinking of upgrading, now may be the time.
Like most graphically intensive video games, Zwift requires a relatively up-to-date computer for the best experience; by using a computer that's below those requirements, you risk running into issues that may not be fixed and sub-par performance. It's also possible that you will become unable to use Zwift on your computer as we increase the graphics quality and improve the Zwift experience.
Check out our hardware page for the full details on computer requirements and other supported devices, including iOS and tvOS devices!