Event ID 8528: Mailbox Storage Limit - Fix Guide 2025

# 1. Enable archive for specific user
Enable-Mailbox john.doe@company.com -Archive

# Verify archive was created
Get-Mailbox john.doe@company.com | Format-List ArchiveStatus, ArchiveDatabase

# 2. Check current archive size (initially 0)0)
Get-MailboxStatistics john.doe@company.com -Archive |
    Select-Object DisplayName, TotalItemSize, ItemCount

# 3. Apply retention policy to auto-move old items-move old items
# First, check if default MRM policy exists
Get-RetentionPolicy

# Apply Default MRM Policy (moves items >2 years to archive)
Set-Mailbox john.doe@company.com -RetentionPolicy "Default MRM Policy"

# 4. Force immediate policy application (normally runs overnight)
Start-ManagedFolderAssistant john.doe@company.com

# 5. Monitor archive migration progress
# Check hourly - items will gradually move to archive
Get-MailboxStatistics john.doe@company.com |
    Select-Object DisplayName, TotalItemSize, ItemCount
Get-MailboxStatistics john.doe@company.com -Archive |
    Select-Object DisplayName, TotalItemSize, ItemCount

# Primary mailbox size should decrease over 24-48 hours-48 hours
# Archive mailbox size should increase correspondingly

# Enable archive for all mailboxes without archives
Get-Mailbox -ResultSize Unlimited |
    Where-Object { $_.ArchiveStatus -eq "None" } |
    Enable-Mailbox -Archive

# Apply retention policy to all users
Get-Mailbox -ResultSize Unlimited |
    Set-Mailbox -RetentionPolicy "Default MRM Policy"

# Force policy application for all mailboxes (runs in background)
Get-Mailbox -ResultSize Unlimited |
    ForEach-Object { Start-ManagedFolderAssistant $_.Alias }

# Generate report of archive status
Get-Mailbox -ResultSize Unlimited |
    Select-Object DisplayName, PrimarySmtpAddress, ArchiveStatus, RetentionPolicy |
    Export-Csv "C:\Temp\ArchiveStatus.csv" -NoTypeInformation

# 1. Find large items (>10 MB) in mailbox10 MB) in mailbox
Search-Mailbox john.doe@company.com \
    -SearchQuery 'size:>10485760' \
    -EstimateResultOnly |
    Format-List

# This shows count and total size of large items without deleting

# 2. Export large items to PST before deletion (backup)
New-MailboxExportRequest \
    -Mailbox john.doe@company.com \
    -FilePath "\\FileServer\Exports\john.doe_large_items.pst" \
    -ContentFilter {MessageSize -gt 10MB}

# Monitor export progress
Get-MailboxExportRequest | Format-Table Name, Status, PercentComplete

# 3. After export completes, delete large items from mailbox
Search-Mailbox john.doe@company.com \
    -SearchQuery 'size:>10485760' \
    -DeleteContent \
    -Force

# 4. Delete old calendar items (>2 years)2 years)
Search-Mailbox john.doe@company.com \
    -SearchQuery 'kind:meetings AND received<01/01/2023'01/2023' \
    -DeleteContent \
    -Force

# 5. Clear Deleted Items and Recoverable Items folders
Search-Mailbox john.doe@company.com \
    -SearchDumpsterOnly \
    -DeleteContent \
    -Force

# 6. Verify space reclaimed
Get-MailboxStatistics john.doe@company.com |
    Select-Object DisplayName, TotalItemSize, ItemCount

# Set default quotas on database (applies to all mailboxes using defaults)
Set-MailboxDatabase "Mailbox Database 01" \
    -IssueWarningQuota 4.5GB \
    -ProhibitSendQuota 5GB \
    -ProhibitSendReceiveQuota 5.5GB

# All new mailboxes and mailboxes with UseDatabaseQuotaDefaults=$true inherit these

# Verify database quota settings
Get-MailboxDatabase "Mailbox Database 01" |
    Format-List Name, IssueWarningQuota, ProhibitSendQuota, ProhibitSendReceiveQuota

# Apply database defaults to existing mailboxes
Get-Mailbox -Database "Mailbox Database 01" -ResultSize Unlimited |
    Set-Mailbox -UseDatabaseQuotaDefaults $true

# Create tiered quota structure based on user roles

# Standard users (5 GB)
Get-Mailbox -ResultSize Unlimited |
    Where-Object { $_.CustomAttribute1 -eq "Standard" } |
    Set-Mailbox \
        -IssueWarningQuota 4.5GB \
        -ProhibitSendQuota 5GB \
        -ProhibitSendReceiveQuota 5.5GB \
        -UseDatabaseQuotaDefaults $false

# Power users (10 GB)
Get-Mailbox -ResultSize Unlimited |
    Where-Object { $_.CustomAttribute1 -eq "PowerUser" } |
    Set-Mailbox \
        -IssueWarningQuota 9GB \
        -ProhibitSendQuota 10GB \
        -ProhibitSendReceiveQuota 11GB \
        -UseDatabaseQuotaDefaults $false

# Executives (25 GB + archive)
Get-Mailbox -ResultSize Unlimited |
    Where-Object { $_.CustomAttribute1 -eq "Executive" } |
    Set-Mailbox \
        -IssueWarningQuota 23GB \
        -ProhibitSendQuota 25GB \
        -ProhibitSendReceiveQuota 27GB \
        -UseDatabaseQuotaDefaults $false

# Enable archive for all executives
Get-Mailbox -ResultSize Unlimited |
    Where-Object { $_.CustomAttribute1 -eq "Executive" } |
    Enable-Mailbox -Archive |
    Set-Mailbox -ArchiveQuota 50GB

# Generate quota compliance report
Get-Mailbox -ResultSize Unlimited |
    Select-Object DisplayName, CustomAttribute1, \
        @{N="Quota(GB)";E={$_.ProhibitSendQuota.Value.ToGB()}}, \
        @{N="Size(GB)";E={(Get-MailboxStatistics $_.Alias).TotalItemSize.Value.ToGB()}}, \
        @{N="Usage%";E={[math]::Round(((Get-MailboxStatistics $_.Alias).TotalItemSize.Value.ToGB() / $_.ProhibitSendQuota.Value.ToGB()) * 100, 1)}} |
    Export-Csv "C:\Temp\QuotaCompliance.csv" -NoTypeInformation

# Save as Invoke-MailboxCleanup.ps1
# Schedule with Task Scheduler to run monthly

$Results = @()

# Get all mailboxes
$Mailboxes = Get-Mailbox -ResultSize Unlimited

foreach ($Mailbox in $Mailboxes) {
    Write-Host "Processing: $($Mailbox.DisplayName)" -ForegroundColor Cyan

    # Get mailbox statistics before cleanup
    $StatsBefore = Get-MailboxStatistics $Mailbox.Alias
    $SizeBefore = $StatsBefore.TotalItemSize.Value.ToGB()

    # 1. Delete items older than 3 years from Deleted Items3 years from Deleted Items
    Search-Mailbox $Mailbox.Alias \
        -SearchQuery 'folder:"Deleted Items" AND received<01/01/2022'01/2022' \
        -DeleteContent -Force -Confirm:$false \
        -WarningAction SilentlyContinue

    # 2. Delete Sent Items older than 2 years2 years
    Search-Mailbox $Mailbox.Alias \
        -SearchQuery 'folder:"Sent Items" AND sent<01/01/2023'01/2023' \
        -DeleteContent -Force -Confirm:$false \
        -WarningAction SilentlyContinue

    # 3. Clear Recoverable Items (dumpster) beyond retention
    Search-Mailbox $Mailbox.Alias \
        -SearchDumpsterOnly \
        -DeleteContent -Force -Confirm:$false \
        -WarningAction SilentlyContinue

    # Get mailbox statistics after cleanup
    Start-Sleep -Seconds 30  # Wait for cleanup to complete
    $StatsAfter = Get-MailboxStatistics $Mailbox.Alias
    $SizeAfter = $StatsAfter.TotalItemSize.Value.ToGB()

    $SpaceReclaimed = [math]::Round($SizeBefore - $SizeAfter, 2)

    $Results += [PSCustomObject]@{
        DisplayName = $Mailbox.DisplayName
        Email = $Mailbox.PrimarySmtpAddress
        SizeBefore_GB = [math]::Round($SizeBefore, 2)
        SizeAfter_GB = [math]::Round($SizeAfter, 2)
        SpaceReclaimed_GB = $SpaceReclaimed
    }

    Write-Host "  Space reclaimed: $SpaceReclaimed GB" -ForegroundColor Green
}

# Export cleanup report
$Results | Export-Csv "C:\Temp\MailboxCleanupReport_$(Get-Date -Format yyyyMMdd).csv"-Format yyyyMMdd).csv" -NoTypeInformation

# Email report to administrators
$TotalReclaimed = ($Results | Measure-Object -Property SpaceReclaimed_GB -Sum).Sum
Send-MailMessage \
    -To "admin@company.com" \
    -From "exchange-monitor@company.com" \
    -Subject "Monthly Mailbox Cleanup Complete - $TotalReclaimed GB Reclaimed" \
    -Body "Mailbox cleanup completed. Total space reclaimed: $TotalReclaimed GB. See attached report." \
    -Attachments "C:\Temp\MailboxCleanupReport_$(Get-Date -Format yyyyMMdd).csv"-Format yyyyMMdd).csv" \
    -SmtpServer "smtp.company.com"