Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires league/object-mapper dev-main -> satisfiable by league/object-mapper[dev-main]. - league/object-mapper dev-main requires ext-fileinfo * -> it is missing from your system. Install or enable PHP's fileinfo extension. To enable extensions, verify that they are enabled in your .ini files: - C:\tools\php\php.ini You can also run `php --ini` in a terminal to see which files are used by PHP in CLI mode. Alternatively, you can run Composer with `--ignore-platform-req=ext-fileinfo` to temporarily ignore these required extensions.