📧 Exchange Online Mailbox Full? Complete Archive Solution Guide

# Executive/Leadership (conservative)
New-RetentionPolicyTag -Name "Executive 2 Year Archive" -Type All `
    -RetentionEnabled $true -AgeLimitForRetention 730 -RetentionAction MoveToArchive
New-RetentionPolicy -Name "Executive Archive Policy" `
    -RetentionPolicyTagLinks "Executive 2 Year Archive"

# Sales/Operations (moderate)
New-RetentionPolicyTag -Name "Sales 6 Month Archive" -Type All `
    -RetentionEnabled $true -AgeLimitForRetention 180 -RetentionAction MoveToArchive
New-RetentionPolicy -Name "Sales Archive Policy" `
    -RetentionPolicyTagLinks "Sales 6 Month Archive"

# Marketing/General (aggressive)
New-RetentionPolicyTag -Name "General 3 Month Archive" -Type All `
    -RetentionEnabled $true -AgeLimitForRetention 90 -RetentionAction MoveToArchive
New-RetentionPolicy -Name "General Archive Policy" `
    -RetentionPolicyTagLinks "General 3 Month Archive"

Enable-Mailbox -Identity [email protected] -AutoExpandingArchive

$report = Get-Mailbox -ResultSize Unlimited | ForEach-Object {
    $primary = Get-MailboxStatistics -Identity $_.UserPrincipalName
    $archive = Get-MailboxStatistics -Archive -Identity $_.UserPrincipalName `
        -ErrorAction SilentlyContinue
    
    [PSCustomObject]@{
        Date              = Get-Date -Format "yyyy-MM-dd"
        DisplayName       = $_.DisplayName
        Email             = $_.UserPrincipalName
        Department        = $_.Department
        RetentionPolicy   = $_.RetentionPolicy
        PrimarySizeGB     = [math]::Round($primary.TotalItemSize.Value.ToBytes()/1GB, 2)
        PrimaryItemCount  = $primary.ItemCount
        ArchiveStatus     = $_.ArchiveStatus
        ArchiveSizeGB     = if($archive) { [math]::Round($archive.TotalItemSize.Value.ToBytes()/1GB, 2) } else { 0 }
        ArchiveItemCount  = if($archive) { $archive.ItemCount } else { 0 }
        TotalSizeGB       = [math]::Round(
            ($primary.TotalItemSize.Value.ToBytes() + 
            $(if($archive) {$archive.TotalItemSize.Value.ToBytes()} else {0}))/1GB, 2)
    }
}

$report | Export-Csv -Path "C:\MailboxReport_$(Get-Date -Format 'yyyyMMdd').csv" `
    -NoTypeInformation

$threshold = 45GB
$largeMailboxes = Get-Mailbox -ResultSize Unlimited | ForEach-Object {
    $stats = Get-MailboxStatistics -Identity $_.UserPrincipalName
    if($stats.TotalItemSize.Value.ToBytes()/1GB -gt $threshold) {
        [PSCustomObject]@{
            User = $_.DisplayName
            Email = $_.UserPrincipalName
            SizeGB = [math]::Round($stats.TotalItemSize.Value.ToBytes()/1GB, 2)
            RetentionPolicy = $_.RetentionPolicy
        }
    }
}

if($largeMailboxes) {
    $largeMailboxes | Format-Table
    # Send email alert to admin
    Send-MailMessage -To "[email protected]" `
        -From "[email protected]" `
        -Subject "Mailbox Storage Alert" `
        -Body ($largeMailboxes | Out-String) `
        -SmtpServer "smtp.office365.com"
}

# Sent Items - 3 months
New-RetentionPolicyTag -Name "Sent Items 3M" -Type SentItems `
    -RetentionEnabled $true -AgeLimitForRetention 90 -RetentionAction MoveToArchive

# Deleted Items - Permanent deletion after 30 days
New-RetentionPolicyTag -Name "Deleted Items 30D Delete" -Type DeletedItems `
    -RetentionEnabled $true -AgeLimitForRetention 30 -RetentionAction PermanentlyDelete

# Inbox - 6 months
New-RetentionPolicyTag -Name "Inbox 6M" -Type Inbox `
    -RetentionEnabled $true -AgeLimitForRetention 180 -RetentionAction MoveToArchive

# Create comprehensive policy
New-RetentionPolicy -Name "Comprehensive Archive Policy" `
    -RetentionPolicyTagLinks "Sent Items 3M","Deleted Items 30D Delete","Inbox 6M"

You are an Exchange Online PowerShell troubleshooting assistant.

Goal: Fix mailbox full issues WITHOUT deleting any emails by using 
archive, retention tags, and policies.

When I give you a user's mailbox or ask about "mailbox full," 
follow this exact process:

1. Connect to Exchange Online:
   Connect-ExchangeOnline

2. Get mailbox sizes:
   Get-Mailbox -ResultSize Unlimited | Get-MailboxStatistics | 
   Select DisplayName,TotalItemSize,ItemCount | 
   Sort-Object TotalItemSize -Descending

3. Get retention policy applied:
   Get-Mailbox -Identity  | Select DisplayName,RetentionPolicy

4. Get archive status:
   Get-Mailbox -Identity  | Select DisplayName,ArchiveStatus

5. Get archive mailbox size:
   Get-MailboxStatistics -Archive -Identity  | 
   Select TotalItemSize,ItemCount

6. Create retention policies if needed:
   New-RetentionPolicyTag -Name "" -Type All 
   -RetentionEnabled $true -AgeLimitForRetention  
   -RetentionAction MoveToArchive
   
   New-RetentionPolicy -Name "" 
   -RetentionPolicyTagLinks ""

7. Assign the retention policy:
   Set-Mailbox -Identity  -RetentionPolicy ""

8. Trigger archive processing:
   Start-ManagedFolderAssistant -Identity 

9. For full report:
   Get-Mailbox -ResultSize Unlimited | ForEach-Object {
     $primary = Get-MailboxStatistics -Identity $_.UserPrincipalName
     $archive = Get-MailboxStatistics -Archive 
       -Identity $_.UserPrincipalName -ErrorAction SilentlyContinue

     [PSCustomObject]@{
        DisplayName       = $_.DisplayName
        RetentionPolicy   = $_.RetentionPolicy
        PrimarySize       = $primary.TotalItemSize
        ArchiveStatus     = $_.ArchiveStatus
        ArchiveSize       = if ($archive) { 
          $archive.TotalItemSize 
        } else { 
          "No Archive Mailbox" 
        }
     }
   } | Sort-Object PrimarySize -Descending

Always output:
- Summary of mailbox size
- Archive size
- Policy applied
- Whether action needed
- Suggested archive period (3/6/8/12/24 months)
- Final commands to fix
- Expected timeline for results