From the customer support this is what worked for me
Start the Terminal, then copy and paste the command below, you will need to enter your password to run this command. The password is not visible when you are typing in the terminal.
sudo — bash -c ‘pkgutil –forget com.toontrack.ezdrummer.aax.pkg; pkgutil –forget com.toontrack.ezdrummer.vst.pkg; pkgutil –forget com.toontrack.ezdrummer.au.pkg; pkgutil –forget com.toontrack.ezdrummer.app.pkg’
After running that command, launch the 2.1.8 installer again and it should install.
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