Here, is what I did to generate a El Capitan VM with virtual box 6:

The following script applies to the current setting of my machine running macOS Mojave 10.14.6 and intends to generate a VM of el Capitan using Virtualbox It took me about 32h, several coffees and some digging into trouble shooting to make my wish come true to be independent from Apple to have access in the future to old 32-bit apps such as the MS Office 2011 in combination with Sente 6…which is simply the dream of any researcher writing manuscripts and have to share it with collaborators around the world using different software configurations and no field codes involved… Thus, as a scientist you need exactly the software like Sente 6 that can deal with any reference format without the need to edit. Papers, (old versions were ok, new versions too slow for unknown reasons), Endnote (too big, too expensive), Mendelay, ok but how to customise reference formats is complicated and unsatisfying. However, none of them can do what Sente 6 can do…. As an example is the legendary Sente 6 (alias thirdpartystreet software) reference manager for scientist and writers, which works like a charm and is the best reference manager I ever experienced. This is fantastic news considering that some apps are just the best in the world but sometimes have been discontinued by software companies. So, the latest nice shot from Apple was to announce no support anymore for 32-bit apps from Catalina alias OSX10.15 on. We all love Apple, however, since Steve Jobs left the “club” we have to live with strange things such as electronic escape buttons, replacement of the famous Apple command bottom by a simple, command button, no fancy and handy display of battery life on laptops, no magnetic power cable, etc. Here is a little snapshot of what is needed to install a “hackintosh” VM on Virtualbox.

El capitan virtualbox