[KevinH]

Okay. I use macOS with Mojave on one of my machines so I created an entirely new user on my system. Logged in as this new user, downloaded Sigil 0.9.14 for mac and installed it on my desktop and tested it.

- Sigil 0.9.14 works just fine if the Mac is set to system Light Theme *before* launching Sigil. Both Preview and BookView work as expected. No black text.

However if you set your mac to Dark Theme before starting Sigil 0.9.14 both Preview and BookView show black text on black backgroud.

Quitting completely out of Sigil, changing the mac to Light Theme and then starting up Sigil fixes things.

The OP simply needs to set their mac to Light theme *before* launching Sigil. Launching Sigil when under Dark mode and then switching to Light will not work. To do that they must exit completely out of Sigil before switching Themes using Sigil's Quit menu.

So
1. Use Sigil's Quit menu to force Sigil to stop running (exit out completely)
2. Switch your mac to Light mode
3. Then and only then start-up Sigil
4. Load your epub.

Both Preview and BookView will then work just fine as testing proves on an iMac with Mojave.

Note: starting up or restarting your mac may not help to exit from Sigil as they are set by default to reopening all apps with windows open when the shutdown or restart was done. This is horrible if any issues exist in the app. I always uncheck the reopen windows box when doing any restart or shutdown to prevent such stupid behaviour.