Got the following error message in WordPress:

Another update is currently in progress.

Solution:

It is an automatic lock to prevent simultaneous core updates. It will be gone after 15 minutes. If you don’t want to wait, delete the record from options table – usually wp_options.

option_name = 'core_updater'

(before WP 4.5)

or

option_name = 'core_updater.lock'

(since WP 4.5)