Catalina install fails - The file “Opt” couldn’t be saved to Macintosh HD - Data
I've just tried to install the latest Catalina version of macOs via the normal Software Update in the system preferences.
After a long while (>30 minutes) I suddenly get the error:
The file “Opt” couldn’t be saved to Macintosh HD - Data. Quit the installer to restart your computer and try again.
I clicked on the restart button, and the whole process started again. After another 20-30minutes, the same error popped up again.
After 3 attempts of this, I used the Recovery and reverted back to Mojave.
This went cleanly, except I now have two Hard Disk Partitions, "Macintosh HD" and "Macintosh HD - Data"
Can anyone help me get Catalina installed and my disk back to one partition please?
Dave
MacBook Air