Fix VSS EventID:8194 with PowerShell

Event ID: 8194 Message: Volume Shadow Copy Service error: Unexpected error querying for the IVssWriterCallback interface. hr = 0x80070005, Access is denied

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The error seems to be caused by the fact that the VSS service is running as LocalSystem and it does not have the right permissions on the DCOM

I created a small PowerShell script to address the issue

Please note that a reboot is required!

The code can be run as in PowerShell, saved in a ps1 file as run as ./filename.ps1 or used in a RMM script

echo “Getting VSS account logon info”;

$svcLogon = Get-WmiObject -Class Win32_Service -ComputerName $env:computername |? { $_.StartName -match $LogonAccount } |? { $_.DisplayName -eq “Volume Shadow Copy” } | select DisplayName, StartName, State, StartMode | Select-Object -ExpandProperty StartName

echo ” VSS is running as ” $svcLogon

echo “Get registry values”

$regValues = Get-Item -Path HKLM:SYSTEM\CurrentControlSet\Services\VSS\VssAccessControl | Select-Object -ExpandProperty Property;

echo “Registry contains” $regValues

echo “Checking to see if it is in the registry”

foreach ($rVal in $regValues ) {
if ($rVal -eq “NT Authority\SYSTEM”) { $regFound = $true; break} else {$regFound = $false }
} ; $regFound;

echo “Is LocalSystem present? ” $regFound

echo “If not existent we will create it, otherwise exit”

echo “Getting VSS account logon info”;

$svcLogon = Get-WmiObject -Class Win32_Service -ComputerName $env:computername |? { $_.StartName -match $LogonAccount } |? { $_.DisplayName -eq “Volume Shadow Copy” } | select DisplayName, StartName, State, StartMode | Select-Object -ExpandProperty StartName

echo ” VSS is running as ” $svcLogon

echo “Get registry values”

$regValues = Get-Item -Path HKLM:SYSTEM\CurrentControlSet\Services\VSS\VssAccessControl | Select-Object -ExpandProperty Property;

echo “Registry contains” $regValues

echo “Checking to see if it is in the registry”

foreach ($rVal in $regValues ) {
if ($rVal -eq “NT Authority\SYSTEM”) { $regFound = $true; break} else {$regFound = $false }
} ; $regFound;

echo “Is LocalSystem present? ” $regFound

echo “If not existent we will create it, otherwise exit”

echo “Getting VSS account logon info”;

$svcLogon = Get-WmiObject -Class Win32_Service -ComputerName $env:computername |? { $_.StartName -match $LogonAccount } |? { $_.DisplayName -eq “Volume Shadow Copy” } | select DisplayName, StartName, State, StartMode | Select-Object -ExpandProperty StartName

echo ” VSS is running as ” $svcLogon

echo “Get registry values”

$regValues = Get-Item -Path HKLM:SYSTEM\CurrentControlSet\Services\VSS\VssAccessControl | Select-Object -ExpandProperty Property;

echo “Registry contains” $regValues

echo “Checking to see if it is in the registry”

foreach ($rVal in $regValues ) {
if ($rVal -eq “NT Authority\SYSTEM”) { $regFound = $true; break} else {$regFound = $false }
} ; $regFound;

echo “Is LocalSystem present? ” $regFound

echo “If not existent we will create it, otherwise exit”

echo “Getting VSS account logon info”;

$svcLogon = Get-WmiObject -Class Win32_Service -ComputerName $env:computername |? { $_.StartName -match $LogonAccount } |? { $_.DisplayName -eq “Volume Shadow Copy” } | select DisplayName, StartName, State, StartMode | Select-Object -ExpandProperty StartName

echo ” VSS is running as ” $svcLogon

echo “Get registry values”

$regValues = Get-Item -Path HKLM:SYSTEM\CurrentControlSet\Services\VSS\VssAccessControl | Select-Object -ExpandProperty Property;

echo “Registry contains” $regValues

echo “Checking to see if it is in the registry”

foreach ($rVal in $regValues ) {
if ($rVal -eq “NT Authority\SYSTEM”) { $regFound = $true; break} else {$regFound = $false }
} ; $regFound;

echo “Is LocalSystem present? ” $regFound

echo “If not existent we will create it, otherwise exit”

We are offering free tech support by email, do not hesitate to Contact Us.