I was trying to install Mautic for the first time. I am using AMPPS (Mac) in localhost and upgraded it to its latest version AMPPS 3.5 with PHP 5.6.21 (I checked it is greater than the required version of PHP 5.6.19). However, it failed to run the installer and got some PHP errors.
The way it was resolved, in case it helps anyone else:
1. Stopped Apache and MySQL
2. Switched AMPPS to use PHP 5.6
3. Deleted the mautic/app/cache folder so it could be regenerated on the next page load.
4. Configured PHP with the following extensions (in php.ini).
5. Started Apache and MySQL
6. Reload http://mautic.dev * and follow the installation process.
* I have configured mautic.dev as an addon domain in AMPPS pointed to the /www/mautic folder.