On April 26, 2021, Apple released Catalina Security Update 2021-002 (19H1030) for macOS 10.15.7.
This security update breaks OpenCL, a framework from Apple used by Observatory for processing images. After installing this update, Observatory will display the error message “An error occurred while initializing OpenCL“ upon launching, and terminates.
The release notes for the security update do not mention OpenCL, and I’m baffled how this got through Apple’s internal QA. Every application using OpenCL directly or indirectly is affected by this, not just Observatory. I’ve immediately filed a bug report with Apple but have not yet received a response.
Big Sur 10.3 (20E232) and Mojave (Security Update 2021-003, 18G9028) have not been affected by this bug. Older macOS versions didn’t receive a security update so they too have not been affected. The regression exists only in the Security Update for macOS Catalina. Before applying it, OpenCL works correctly, but after applying it, it does not anymore.
I would normally never recommend this, but until this is resolved by Apple, please do not install Catalina Security Update 2021-002.
Update 2021-05-06: Catalina Security Update Developer Beta 2021-003 fixes the issue, so I expect it to be resolved in the upcoming Catalina Security Update 2021-003.