Prior to the release of any new macOS, we make a concerted effort to test as many of our products as we can with the new OS, using a variety of hosts and configurations. The Helios FX series of products is no exception. Test results showed no significant changes in behavior or performance from previous compatible OS versions.
However, in the days since macOS Catalina was released, various online publications and individuals have noted problems when using specific GPUs in combination with Catalina and the 2018 Mac mini series.
We decided to investigate this ourselves, and the results have been mixed thus far. While we cannot definitively say that a 2018 Mac mini running Catalina will not work with the Helios FX or other eGPUs, there are clearly some scenarios
Specifically, we are considering a change to our compatibility listings with respect to Radeon RX x00 series cards, such as the RX 480 and RX 580 series, as well as a limited number of specialized cards like the Radeon Pro WX 7100. Thus far, we have encountered no critical issues with higher-end cards like the Vega 56 and 64 series, and only limited issues or pre-existing issues with the Radeon VII and Radeon Pro WX 8200. Again this is all specific to the 2018 Mac mini series; we do not have any reason at this time to think it impacts other series like the MacBook Pro.
Tests are ongoing, but at this time, if you are running a 2018 Mac mini with an eGPU like the Helios FX, on 10.13.4 High Sierra – 10.14.6 Mojave, and you are not experiencing any issues, it may be a good idea to delay your upgrade to macOS 10.15 Catalina for the time being.