soundtrack pro 3.0.1 can't run with OS High Sierra
I used for quite a long time Soundtrack Pro, version 3.0.1 together with Final Cut Pro, Compressor etc. on my iMac.
But now I upgraded the Mac to the High Sierrs OS, I can't use this version of Soundtrack Pro.
When I go the the Apple Support Site, I am given the choice of downloading the Soundtrack Pro 2.0.2 update.
Then when I want to install it (requesting me to change my security setting to accept unidentified developers, I can't install it in my running disk. I get a message "Soundtrack Pro Update can't be installed on this disk. Your computer does not need this update".
So please let me know what I can do to keep using my Soundtrack Pro version or get an update that can run in the OS High Sierra.
I dont want to face a situation in which I need to download a new Soundtrack Pro version and charging me again for that version (paying twice for more or less the same application is a nonsense.
MacBook Pro (Retina, Mid 2012), IOS 10.13.1 (not listed here)