«Target already exists (set extra.magento-force to override)»

Administration Installation
,
1

If you got the message:

Target already exists (set extra.magento-force to override)

so you need enable extra.magento-force option in the root composer.json file:

{
	(...)
	"extra": {
		"magento-force": true,
         (...)
	},
	(...)
}
2

Just for completion, in Magento 2 own composer.json it states “override” and not true (both are working but it’s nice to follow M2):

“extra”: {
“magento-force”: “override”
}