How to fix “Installation Failed.” error while upgrading WordPress.

WordPress frequently provides updates which can be applied Automatically or using One Click option.
WordPress can also be upgraded using Manual Update procedure.

Below is One of the error which can occur during the update,

Upgrade WordPress

Downloading update from http://wordpress.org/…

Unpacking the update.

Could not copy file.: wordpress/wp-admin/install.php

Installation Failed.

The most common reason of the above error is, you do not have enough space on server.

When you buy hosting, you are assigned a limited space for the hosting on server.
This can be verified from your hosting Control Panel.

Either you can ask for more space from your hosting provider or remove some files to create space for the upgrade of WordPress.

If you have an old hosting account you must have log files or website backups on the server which can be removed (You can download these before removing to have local backup).