How to Update User Email Address in SharePoint using PowerShell?

Problem: SharePoint workflows failed because, user has no email address!

You can get the user's Email address with this PowerShell one-liner:

(Get-SPUser -Identity "Crescent\bourgeois" -Web "http://portal.crescent.com/projectpipeline").email

Solution is simple! SharePoint user has no email address, so add email address to users to resolve the issue!

How to update SharePoint user email address?
To update user email address, Use, Set-SPUser cmdlet. Here are some examples:
Syntax:

Set-SPUser -Identity "i:0#.w|Domain\username" -Email "email@domain.com" -Web http://sharepoint-site-url

Example:

Set-SPUser -Identity "i:0#.w|Crescent\Salaudeen" -Email "Salaudeen@crescent.com" -Web http://intranet.crescent.com/

This sets the Email ID of the user to given Email for entire site collection.

Change user email address from Active Directory:
You can Sync User's Email ID from Active Directory

Set-SPUser -Identity "i:0#.w|Domain\username" -Web "http://sharepoint-site-url" -SyncFromAD

Set-SPUser -Identity "i:0#.w|Crescent\Salaudeen" -Web "http://intranet.crescent.com/" -SyncFromAD

This script syncs user properties such as Display Name, Email, Department, etc from Active directory. Here is the result of updated user Email:

PowerShell script to update User Email address for all Sites in the web application:
Use this script to update user's Email address for the entire web application.

Add-PSSnapin Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue
 
$WebAppURL="http://intranet.crescent.com"
$UserAccount="i:0#.w|Crescent\Salaudeen"

#Update Email for all sites in the web application
Get-SPWebApplication $WebAppURL | Get-SPSite -Limit All | Foreach-object {
    
    Write-host "Processing:" $_.Rootweb.URL

    #Get the User's Current Display Name and E-mail
    $User = Get-SPUser -Identity $UserAccount -Web $_.Rootweb.URL

    if($User -ne $null)
    {
        Set-SPUser -Identity "i:0#.w|Crescent\Salaudeen" -Email "Salaudeen@crescent.com" –Web $_.Rootweb.URL
    }
}

To Sync All user details such as Email, Display name, etc from Active directory, use:

Get-SPUser -Web http://web-app-url | Set-SPUser –SyncFromAD