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macOS 10.15 Catalina released - DO NOT UPGRADE

This afternoon, Apple released macOS 10.15 Catalina. ISC strongly recommends that Schools, Centers, and other University constituents do not upgrade, waiting until ISC has issued an update on the status of Catalina.

macOS 10.15 Catalina is the first version of macOS that does not support 32-bit applications. Since many existing applications are still 32-bit only, this lack of support may cause serious compatibility issues in Penn's computing environment.

At this time, ISC strongly advises against upgrading until extensive testing has been completed; not only by ISC but also by local IT staff to ensure compatibility of department-specific software. For several months, ISC and others across the University have been performing vigorous testing on macOS 10.15 beta versions to identify problems and potential workarounds. However, it may take some time to determine the true scope of the issues that will arise.

Frequently-used products on campus that are known to be 32-bit only or contain 32-bit elements include Fetch, DataComet-Secure, Adobe Creative Cloud, and Symantec Endpoint Protection.

Please see the article below for further details on known compatibility issues with macOS 10.15 Catalina. ISC will continue to update this article as new compatibility issues are discovered.

If you have any questions or would like to report additional compatibility issues to be added to the above article, please contact ISC Client Care at  or at