“Alert me” option missing in SharePoint

Issue Description

Recently in our SharePoint 2013 farm, I had noticed that the "Alert Me" button was missing from library tab in 

SharePoint Ribbon.

Resolution

1. Please try this article first -  “Alert me” option missing in SharePoint

2. If this solution dint help, try using the below STSADM or PowerShell command to enable the alerts:

STSADM:

stsadm -o setproperty -pn alerts-enabled -pv true -url http://webappURL

PowerShell

$webapp=Get-SPWebApplication "http://webappURL"

$webapp.AlertsEnabled = $true

$webapp.Update()