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OT Installation on Catalina 10.15.4 - Knowledgebase / ALMA Observing Tool (OT) - ALMA Science

OT Installation on Catalina 10.15.4

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Mac users running Catalina (10.15) may be aware that installation of the OT is more difficult than on other versions of OS X i.e. the new Installer cannot be used. Unfortunately, the recent release of 10.15.4 has made things even more difficult and this article is designed to guide you through the slightly altered tarball installation procedure.

The existing instructions for installing the tarball version are still valid, but when running the ‘’ script the OS will display a pop-up noting the potential existence of malware and give two options, ‘Move to Bin’ and ‘Cancel’. The correct procedure is to select ‘Cancel’ and then to ‘cd’ up one directory as usual. Despite the cancellation of the install process the ‘’ executable will have been created as usual.

At this point it is necessary to reassure the OS that the software is trusted and this can be done by opening ‘Security & Privacy’ and clicking ‘Allow Anyway’. It should now be possible to start the OT by running ‘’. This will bring up yet another warning dialogue, but this one will give the option to run the OT i.e. select ‘Open’.

Finally, if you are working from behind a firewall, the setup script should be run again before starting the OT.