WordPress upgrade tools is way AWESOME! It help us upgrade core system, plugins, and themes easily. However, as with many other human products, failed is one of it’s features.
When wordpress doing upgrade, it put system into maintenance mode. After upgrading processes finished, it bring back to live mode and ready to serve traffic. However, when this process failed, you’ll ended up in White Screen Of Death with BIG “Briefly unavailable for scheduled maintenance. Check back in a minute.” sentences in it. You can do nothing to it, because it also affect the admin panel. So, how do we fix this problem? Hah! easy.
When wordpress activating it’s maintenance mode, it created
.maintenancefile on your server, where wp-config.php reside. Just remove that
.maintenancefile and you’ll be back to live!
Horray for pocoyo *eh*!
To remove it, you will have to login to your fav FTP client or access via your hosting’s CPanel.