Error 0x8004010F: Outlook Cannot Connect - Complete Fix Guide

# Verify Autodiscover virtual directory URLs
Get-AutodiscoverVirtualDirectory | Format-List Server, InternalUrl, ExternalUrl

# Correct the URLs if needed
Get-AutodiscoverVirtualDirectory | Set-AutodiscoverVirtualDirectory -InternalUrl "https://mail.domain.com/autodiscover/autodiscover.xml" -ExternalUrl "https://mail.domain.com/autodiscover/autodiscover.xml"

# Check SCP in Active Directory
Get-ClientAccessService | Format-List Name, AutoDiscoverServiceInternalUri

# Set correct SCP
Set-ClientAccessService -Identity "YOURSERVER" -AutoDiscoverServiceInternalUri "https://mail.domain.com/autodiscover/autodiscover.xml"

# Force AD replication
Invoke-Command -ComputerName DC01 -ScriptBlock { repadmin /syncall /APed }

# Test Autodiscover for specific user
Test-OutlookWebServices -Identity user@domain.com |
    Where-Object {$_.Type -eq "Autodiscover"} | Format-List

# Restart IIS to apply changes
iisreset /noforce

# Get current GUIDs
$mailbox = Get-Mailbox user@domain.com
Write-Host "Exchange GUID: $($mailbox.ExchangeGuid)"

$adUser = Get-ADUser -Identity "username" -Properties msExchMailboxGuid
$adGuidBytes = $adUser.msExchMailboxGuid
$adGuid = if ($adGuidBytes) { [GUID]$adGuidBytes } else { "Not Set" }
Write-Host "AD GUID: $adGuid"

# If AD GUID is different, update it to match Exchange
# This is needed after certain restore/migration scenarios
if ($adGuid -ne $mailbox.ExchangeGuid -and $adGuid -ne "Not Set") {
    Write-Host "Updating AD to match Exchange GUID..."

    # Convert GUID to byte array for AD
    $guidBytes = $mailbox.ExchangeGuid.ToByteArray()

    # Update AD attribute
    Set-ADUser -Identity "username" -Replace @{msExchMailboxGuid = $guidBytes}

    Write-Host "AD msExchMailboxGuid updated. Waiting for replication..."
    Start-Sleep -Seconds 30
}

# Alternatively, if Exchange needs updating (rare)
# Set-Mailbox user@domain.com -ExchangeGuid $adGuid-ExchangeGuid $adGuid

# Verify the fix
$adUser = Get-ADUser -Identity "username" -Properties msExchMailboxGuid
$newAdGuid = [GUID]$adUser.msExchMailboxGuid
Write-Host "New AD GUID: $newAdGuid"
Write-Host "Exchange GUID: $($mailbox.ExchangeGuid)"

# Locate ScanPST (Inbox Repair Tool)
$scanpst = @(
    "C:\Program Files\Microsoft Office\root\Office16\SCANPST.EXE",
    "C:\Program Files (x86)\Microsoft Office\root\Office16\SCANPST.EXE",
    "C:\Program Files\Microsoft Office\Office16\SCANPST.EXE"
)
$scanpstPath = $scanpst | Where-Object { Test-Path $_ } | Select-Object -First 1

if ($scanpstPath) {
    Write-Host "Found ScanPST at: $scanpstPath"

    # Close Outlook first
    Get-Process Outlook -ErrorAction SilentlyContinue | Stop-Process -Force

    # Find OST files
    $ostFiles = Get-ChildItem "$env:LOCALAPPDATA\Microsoft\Outlook" -Filter "*.ost"
    Write-Host "OST files found:"
    $ostFiles | ForEach-Object { Write-Host "  $($_.FullName)" }

    # Run ScanPST (opens GUI)
    Start-Process $scanpstPath
    Write-Host "`nScanPST opened. Select the OST file and run repair."
} else {
    Write-Host "ScanPST not found. Try reinstalling Office."
}

# Alternative: Delete OST to force recreation
# (Only do this if repair fails - will require full mailbox re-sync)
$ostPath = "$env:LOCALAPPDATA\Microsoft\Outlook"
$ost = Get-ChildItem $ostPath -Filter "*.ost" | Select-Object -First 1
if ($ost) {
    $backup = $ost.FullName + ".bak"
    Move-Item $ost.FullName $backup
    Write-Host "OST backed up to: $backup"
    Write-Host "Outlook will create new OST on next launch."
}

# Close Outlook
Get-Process Outlook -ErrorAction SilentlyContinue | Stop-Process -Force
Start-Sleep -Seconds 3

# Create new profile via registry (Outlook 2016/365)365)
$profileName = "NewExchangeProfile"
$email = "user@domain.com"

# Create profile key
$profilePath = "HKCU:\Software\Microsoft\Office\16.0\Outlook\Profiles\$profileName"0\Outlook\Profiles\$profileName"
New-Item -Path $profilePath -Force | Out-Null

# Set as default profile
Set-ItemProperty -Path "HKCU:\Software\Microsoft\Office\16.0\Outlook"0\Outlook" -Name "DefaultProfile" -Value $profileName

# Launch Outlook with new profile (will prompt for setup)
Start-Process "outlook.exe" -ArgumentList "/profile $profileName"

Write-Host "Outlook launched with new profile: $profileName"
Write-Host "Follow the prompts to configure your Exchange account."

# Alternative: Silent profile creation with PRF file
# Create a PRF file for automated setup
$prfContent = @"
[General]
Custom=1
ProfileName=$profileName

[Service1]
OverwriteExistingService=No
UniqueService=Yes
MailboxName=$email
HomeServer=mail.domain.com
"$profileName

[Service1]
OverwriteExistingService=No
UniqueService=Yes
MailboxName=$email
HomeServer=mail.domain.com
"@

$prfPath = "$env:TEMP\outlook_$profileName.prf"$profileName.prf"
Set-Content -Path $prfPath -Value $prfContent
Start-Process "outlook.exe" -ArgumentList "/importprf $prfPath"

# Check mailbox health
Test-MAPIConnectivity -Identity user@domain.com | Format-List

# Run mailbox repair (checks for corruption)
New-MailboxRepairRequest -Mailbox user@domain.com -CorruptionType ProvisionedFolder, SearchFolder, AggregateCounts, Folderview

# Check repair status
Get-MailboxRepairRequest -Mailbox user@domain.com | Format-List

# If mailbox appears corrupted, check database
$db = (Get-Mailbox user@domain.com).Database
Get-MailboxDatabase $db -Status | Format-List Name, DatabaseSize, AvailableNewMailboxSpace

# Export and reimport mailbox if severely corrupted
# Create a PST export
New-MailboxExportRequest -Mailbox user@domain.com -FilePath "\\server\share\user_backup.pst"

# Monitor export progress
Get-MailboxExportRequest -Mailbox user@domain.com | Get-MailboxExportRequestStatistics

# If needed, disable and re-enable mailbox (extreme case)
# WARNING: This disconnects the mailbox temporarily
# Disable-Mailbox user@domain.com -Archive:$false-Archive:$false
# Connect-Mailbox -Identity "User Mailbox" -Database DB01 -User "DOMAIN\user"-Identity "User Mailbox" -Database DB01 -User "DOMAIN\user"