When running the UI Designer on Mac it is very slow. So slow you can’t use it. Starting takes 5+ minutes, opening a document is similar. When looking at the ActivityManager the UI Designer process is marked as “Not responding”.
We identified that the root cause could be Sophos: Whenever we open a document, the Sophos process spins up and uses lots of CPU. When u kill the Sophos process, the pending operation in the UI Designer is finished almost immediately.
Work around: In the Apps there is a Sophos App. In there you can restrict the scanning process so that the directory with the A12 tools is not scanned anymore 