Hello Everyone,
If you need to force the default email format to HTML for all your mailboxes, you can do so with one line of PowerShell.
To do that, you first need to connect to Exchange Online :
$LiveCred = Get-Credential$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://outlook.office365.com/powershell-liveid/ -Credential $LiveCred -Authentication Basic -AllowRedirectionImport-PSSession $SessionOnce you are connected, you can force the default format to HTML for every mailboxes with this command :
Get-Mailbox | Set-MailboxMessageConfiguration -DefaultFormat Html