If you have been given a “validation code” for your Quickbooks, you can easily get to the registration window where it asks you for this code without having to go through the registration shenanigans. Open QuickBooks, select Help and then About QuickBooks. When the product splash screen shows, press Ctrl-R-P (hold the Ctrl key down then press R and P in succession). This opens the window that lets you enter your validation code.

Use powershell to set the spam/junk filter operation for all users:

1. $UserCredential = Get-Credential
2. $Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://outlook.office365.com/powershell-liveid/ -Credential $UserCredential -Authentication Basic -AllowRedirection
3. Import-PSSession $Session
4. Get-Mailbox
5. Get-Mailbox | Set-MailboxJunkEmailConfiguration –Enabled $False

This disables the filter for all. Change $False to $True in #5 to enable the filter for all.