What does Event ID 5000 mean in Exchange?

Event ID 5000 indicates the Microsoft Exchange Information Store service failed to initialize properly. This prevents all mailbox databases from mounting, blocking user access to email, calendar, and contacts.

Why does the Exchange Information Store fail to start?

Common causes include Active Directory connectivity issues, corrupted ESE database engine files, insufficient system resources, missing service dependencies, damaged Exchange installation, or permission problems with Exchange service accounts.

How do I fix Event ID 5000 in Exchange?

Start by checking Active Directory connectivity and service account permissions. Verify dependent services are running, check disk space and memory, and ensure Exchange binaries are intact. Running Exchange Setup in recovery mode may be needed for severe cases.

Can corrupted database files cause Event ID 5000?

While database corruption typically causes mount failures with different event IDs, severe corruption or issues with the ESE database engine components can prevent the Information Store service from initializing, triggering Event ID 5000.

Should I reinstall Exchange to fix Event ID 5000?

Reinstallation is rarely necessary. First try restarting services, checking AD connectivity, verifying permissions, and running Setup /PrepareAD. If needed, run Setup /Mode:RecoverServer which repairs the installation without affecting databases.

What does Event ID 5000 mean in Exchange?

Event ID 5000 indicates the Microsoft Exchange Information Store service failed to initialize properly. This prevents all mailbox databases from mounting, blocking user access to email, calendar, and contacts.

Why does the Exchange Information Store fail to start?

Common causes include Active Directory connectivity issues, corrupted ESE database engine files, insufficient system resources, missing service dependencies, damaged Exchange installation, or permission problems with Exchange service accounts.

How do I fix Event ID 5000 in Exchange?

Start by checking Active Directory connectivity and service account permissions. Verify dependent services are running, check disk space and memory, and ensure Exchange binaries are intact. Running Exchange Setup in recovery mode may be needed for severe cases.

Can corrupted database files cause Event ID 5000?

While database corruption typically causes mount failures with different event IDs, severe corruption or issues with the ESE database engine components can prevent the Information Store service from initializing, triggering Event ID 5000.

Should I reinstall Exchange to fix Event ID 5000?

Reinstallation is rarely necessary. First try restarting services, checking AD connectivity, verifying permissions, and running Setup /PrepareAD. If needed, run Setup /Mode:RecoverServer which repairs the installation without affecting databases.

Event ID 5000: Unable to Initiate Store

Event ID 5000 indicates the Exchange Information Store service cannot start, which means no mailbox databases can mount and all email access is blocked. This guide walks you through diagnosing the failure and restoring the Information Store.

Our Exchange Emergency Support team provides rapid response for critical service failures.

Error Overview: Information Store Failure

The Microsoft Exchange Information Store (MSExchangeIS) service manages all mailbox database operations. When it fails to initialize, no databases can mount and all mailbox access stops completely.

Typical Event Log Entry

# Event ID 5000
Log Name:      Application
Source:        MSExchangeIS
Event ID:      5000
Level:         Error
Description:
Unable to initialize the Microsoft Exchange Information Store
service. The following error occurred:
The database engine failed to initialize.

# Associated errors may include:
Event ID: 5001 - Failed to initialize MAPI
Event ID: 1000 - ESE engine error
Event ID: 1087 - Database recovery failed

Symptoms & Business Impact

What Admins See:

MSExchangeIS service fails to start
Event ID 5000 in Application log
All mailbox databases show Dismounted
Other Exchange services may fail to start
OWA and Outlook connections fail

Business Impact:

Complete email outage for all users
No access to calendars, contacts, or tasks
Mobile devices cannot sync
Business-critical communications halted

Check Current State

# Check Information Store service
Get-Service MSExchangeIS | Select-Object Name, Status, StartType

# Check all Exchange services
Get-Service *Exchange* | Select-Object Name, Status | Format-Table -AutoSize

# Check database mount status
Get-MailboxDatabase -Status | Select-Object Name, Mounted, Server | Format-Table

# Get recent 5000 events
Get-EventLog -LogName Application -Source MSExchangeIS -Newest 20 | Where-Object { $_.EventID -eq 5000 } | Format-List TimeGenerated, Message

Common Causes

1. Active Directory Connectivity (30%)

Exchange cannot reach domain controllers or global catalog servers to authenticate and read configuration.

2. Service Account Issues (25%)

Exchange service account password expired, account disabled, or permissions removed from required groups.

3. ESE Database Engine (20%)

Corrupted ESE engine files or registry entries preventing database engine initialization.

4. Resource Exhaustion (15%)

Insufficient memory, disk space, or other system resources preventing service startup.

5. Dependent Service Failure (10%)

Required services like RPC, LDAP, or other Exchange services failed to start.

Quick Diagnosis

Step 1: Check Active Directory

# Test AD connectivity
nltest /dsgetdc:$env:USERDNSDOMAIN /force

# Test Global Catalog
nltest /dsgetdc:$env:USERDNSDOMAIN /gc /force

# Verify LDAP port connectivity
Test-NetConnection -ComputerName (Get-ADDomainController).HostName -Port 389

# Check secure channel
Test-ComputerSecureChannel -Repair

# Verify Exchange can read from AD
Get-ExchangeServer | Select-Object Name, AdminDisplayVersion

Step 2: Check Service Account

# Check Exchange service accounts
$exchServices = Get-WmiObject Win32_Service | Where-Object { $_.Name -like "*Exchange*" }
$exchServices | Select-Object Name, StartName, State | Format-Table

# Verify Local System or Network Service accounts
# Exchange typically uses LocalSystem for most services

# Check if account is disabled or locked
$computerAccount = Get-ADComputer -Identity $env:COMPUTERNAME -Properties *
$computerAccount | Select-Object Enabled, LockedOut, PasswordExpired, PasswordLastSet

Step 3: Check Resources

# Check disk space
Get-WmiObject Win32_LogicalDisk | Where-Object { $_.DriveType -eq 3 } | Select-Object DeviceID, @{N='FreeGB';E={[math]::Round($_.FreeSpace/1GB,2)}}

# Check memory
$os = Get-WmiObject Win32_OperatingSystem
Write-Host "Total Memory: $([math]::Round($os.TotalVisibleMemorySize/1MB,2)) GB"2)) GB"
Write-Host "Free Memory: $([math]::Round($os.FreePhysicalMemory/1MB,2)) GB"2)) GB"

# Check dependent services
$deps = @("RpcSs", "EventLog", "LanmanServer", "Netlogon")
foreach ($dep in $deps) {
    $svc = Get-Service -Name $dep -ErrorAction SilentlyContinue
    Write-Host "$dep : $($svc.Status)"$svc.Status)"
}

Quick Fix

Restart Exchange Services in Order

# Stop all Exchange services
Write-Host "Stopping Exchange services..."
Get-Service *Exchange* | Where-Object { $_.Status -eq "Running" } | Stop-Service -Force

# Wait for services to stop
Start-Sleep -Seconds 30

# Start services in correct order
Write-Host "Starting Exchange services..."
Start-Service MSExchangeADTopology
Start-Sleep -Seconds 10

Start-Service MSExchangeServiceHost
Start-Sleep -Seconds 10

Start-Service MSExchangeIS
Start-Sleep -Seconds 20

# Check status
Get-Service MSExchangeIS | Select-Object Name, Status

# If successful, databases should mount automatically
Get-MailboxDatabase -Status | Select-Object Name, Mounted

Detailed Solutions

Solution 1: Fix AD Connectivity

Resolve Active Directory Issues

# Reset computer account password
Reset-ComputerMachinePassword -Credential (Get-Credential)

# Or rejoin domain (more disruptive)
# Remove-Computer -UnjoinDomaincredential (Get-Credential) -Force -Restart-UnjoinDomaincredential (Get-Credential) -Force -Restart
# Add-Computer -DomainName "domain.local" -Credential (Get-Credential) -Restart-DomainName "domain.local" -Credential (Get-Credential) -Restart

# Clear Kerberos tickets
klist purge

# Register DNS records
ipconfig /registerdns

# Flush DNS cache
ipconfig /flushdns

# Verify connectivity after fix
nltest /dsgetdc:$env:USERDNSDOMAIN /force

Solution 2: Repair ESE Engine

Check and Repair Database Engine

# Check ESE version
$esePath = "$env:ExchangeInstallPath\Bin\ese.dll"
(Get-Item $esePath).VersionInfo | Select-Object FileVersion, ProductVersion

# Verify ESE registry entries
$eseReg = "HKLM:\SOFTWARE\Microsoft\ESE\Global\OS\Windows 10.0"0"
Get-ItemProperty -Path $eseReg -ErrorAction SilentlyContinue

# Re-register ESE DLLs
$exchBin = "$env:ExchangeInstallPath\Bin"
Set-Location $exchBin
regsvr32 /s ese.dll
regsvr32 /s esebcli2.dll

# Verify Exchange binaries are intact
$setupPath = "$env:ExchangeInstallPath\Bin\Setup.exe"
if (Test-Path $setupPath) {
    Write-Host "Exchange binaries present"
} else {
    Write-Host "Exchange binaries may be missing - need recovery" -ForegroundColor Red
}

Solution 3: Run Exchange Recovery

Recovery Mode Installation

# RecoverServer mode reinstalls Exchange without affecting databases
# Run from Exchange installation media

# Mount or extract Exchange installation files
$setupPath = "D:\Setup.exe"  # Path to Exchange setup

# Run recovery mode (takes 30-60 minutes)-60 minutes)
Start-Process $setupPath -ArgumentList "/Mode:RecoverServer" -Wait

# Alternatively, use PrepareAD to fix AD schema issues
Start-Process $setupPath -ArgumentList "/PrepareAD /IAcceptExchangeServerLicenseTerms" -Wait

# After recovery, restart all Exchange services
Get-Service *Exchange* | Restart-Service -Force

Solution 4: Check Service Dependencies

Verify and Start Dependencies

# List dependencies for Information Store
$svc = Get-Service MSExchangeIS
$svc.DependentServices | Select-Object Name, Status
$svc.ServicesDependedOn | Select-Object Name, Status

# Ensure all dependent services are running
$dependencies = @(
    "MSExchangeADTopology",
    "RpcSs",
    "LanmanServer",
    "EventLog",
    "Netlogon"
)

foreach ($dep in $dependencies) {
    $service = Get-Service -Name $dep -ErrorAction SilentlyContinue
    if ($service.Status -ne "Running") {
        Write-Host "Starting $dep..."
        Start-Service -Name $dep -ErrorAction SilentlyContinue
        Start-Sleep -Seconds 5
    }
    Write-Host "$dep : $((Get-Service $dep).Status)"Get-Service $dep).Status)"
}

# Now try starting Information Store
Start-Service MSExchangeIS

Verify the Fix

Verify Service and Database Status

# Check Information Store is running
$is = Get-Service MSExchangeIS
Write-Host "Information Store: $($is.Status)"

if ($is.Status -eq "Running") {
    Write-Host "Service started successfully" -ForegroundColor Green

    # Check databases are mounted
    $dbs = Get-MailboxDatabase -Status
    $dbs | Select-Object Name, Mounted | Format-Table

    $unmounted = $dbs | Where-Object { -not $_.Mounted }
    if ($unmounted) {
        Write-Host "Some databases not mounted. Attempting mount..."
        $unmounted | ForEach-Object { Mount-Database -Identity $_.Name -Confirm:$false }
    }

    # Test mailbox access
    Test-MAPIConnectivity -Identity "administrator@domain.com"
} else {
    Write-Host "Service still not running" -ForegroundColor Red
    Get-EventLog -LogName Application -Source MSExchangeIS -Newest 5 | Format-List
}

Prevention Tips

Best Practices

Monitor Exchange service health proactively
Ensure redundant domain controllers are available
Maintain minimum 20% free disk space
Keep Exchange patched with latest CU and SU
Document service account configurations
Test disaster recovery procedures regularly
Configure service restart on failure in SCM

When to Escalate

Contact Exchange specialists if:

Service fails to start after all troubleshooting
RecoverServer mode fails
Multiple Exchange servers affected simultaneously
Database corruption suspected
Need rapid recovery for business continuity

Need Expert Help?

Our Exchange Emergency Team provides rapid response for critical Information Store failures.