diff --git a/doc/100-General/10-Changelog.md b/doc/100-General/10-Changelog.md
index ff662b3..06db311 100644
--- a/doc/100-General/10-Changelog.md
+++ b/doc/100-General/10-Changelog.md
@@ -17,6 +17,10 @@ Released closed milestones can be found on [GitHub](https://github.com/Icinga/ic
 * [#362](https://github.com/Icinga/icinga-powershell-framework/issues/362) Fixes repository component installation from file share locations
 * [#363](https://github.com/Icinga/icinga-powershell-framework/issues/363) Fixes unneeded continue for JEA process lookup, in case no JEA pid is present
 
+### Enhancements
+
+* [#364](https://github.com/Icinga/icinga-powershell-framework/pull/364) Fixes a long lookup for the user table on environments with a large Active Directory
+
 ## 1.6.0 (2021-09-07)
 
 [Issue and PRs](https://github.com/Icinga/icinga-powershell-framework/milestone/15?closed=1)
diff --git a/lib/core/tools/Get-IcingaUserSID.psm1 b/lib/core/tools/Get-IcingaUserSID.psm1
index e96602b..9c3fa8d 100644
--- a/lib/core/tools/Get-IcingaUserSID.psm1
+++ b/lib/core/tools/Get-IcingaUserSID.psm1
@@ -24,12 +24,12 @@ function Get-IcingaUserSID()
             $NTUser          = New-Object System.Security.Principal.NTAccount($UserData.Domain, $UserData.User);
             $SecurityData    = $NTUser.Translate([System.Security.Principal.SecurityIdentifier]);
         } catch {
-            throw $_.Exception;
+            return $null;
         }
     }
 
     if ($null -eq $SecurityData) {
-        throw 'Failed to fetch user information from system';
+        return $null;
     }
 
     return $SecurityData.Value;
diff --git a/lib/core/windows/New-IcingaWindowsUser.psm1 b/lib/core/windows/New-IcingaWindowsUser.psm1
index 366af65..14b4b8d 100644
--- a/lib/core/windows/New-IcingaWindowsUser.psm1
+++ b/lib/core/windows/New-IcingaWindowsUser.psm1
@@ -14,7 +14,12 @@ function New-IcingaWindowsUser()
     }
 
     $UserMetadata = Get-IcingaWindowsUserMetadata;
-    $UserConfig   = Get-IcingaWindowsInformation -Class 'Win32_UserAccount' | Where-Object { $_.Name -eq $IcingaUser };
+    $UserConfig   = $null;
+
+    $SID = Get-IcingaUserSID -User $IcingaUser;
+    if ([string]::IsNullOrEmpty($SID) -eq $FALSE) {
+        $UserConfig = Get-IcingaWindowsInformation -Class 'Win32_UserAccount' -Filter ([string]::Format("SID = '{0}'", $SID));
+    }
 
     if ($null -ne $UserConfig) {
 
@@ -32,6 +37,8 @@ function New-IcingaWindowsUser()
             }
 
             Write-IcingaConsoleNotice 'User updated successfully.';
+        } else {
+            Write-IcingaConsoleWarning 'User "{0}" is not managed by Icinga for Windows. No changes were made.' -Objects $IcingaUser;
         }
 
         return @{
@@ -61,7 +68,8 @@ function New-IcingaWindowsUser()
     $LocalUserGroup.Add("WinNT://$Env:COMPUTERNAME/$IcingaUser,user")
     #>
 
-    $UserConfig = Get-IcingaWindowsInformation -Class 'Win32_UserAccount' | Where-Object { $_.Name -eq $IcingaUser };
+    $SID        = Get-IcingaUserSID -User $IcingaUser;
+    $UserConfig = Get-IcingaWindowsInformation -Class 'Win32_UserAccount' -Filter ([string]::Format("SID = '{0}'", $SID));
 
     Write-IcingaConsoleNotice 'User was successfully created.';
 
diff --git a/lib/core/windows/Remove-IcingaWindowsUser.psm1 b/lib/core/windows/Remove-IcingaWindowsUser.psm1
index ab23a7a..8d0b9a2 100644
--- a/lib/core/windows/Remove-IcingaWindowsUser.psm1
+++ b/lib/core/windows/Remove-IcingaWindowsUser.psm1
@@ -4,21 +4,26 @@ function Remove-IcingaWindowsUser()
         $IcingaUser = 'icinga'
     );
 
-    $UserConfig = Get-IcingaWindowsInformation -Class 'Win32_UserAccount' | Where-Object { $_.Name -eq $IcingaUser };
+    $SID = Get-IcingaUserSID -User $IcingaUser;
 
     if ((Test-IcingaManagedUser -IcingaUser $IcingaUser) -eq $FALSE) {
         Write-IcingaConsoleNotice 'The user "{0}" is not present or not created by Icinga for Windows. Unable to remove user' -Objects $IcingaUser;
-        return;
+
+        return @{
+            'User' = $IcingaUser;
+            'SID'  = $SID;
+        };
     }
 
-    $Result = Start-IcingaProcess -Executable 'net' -Arguments ([string]::Format('user "{0}" /DELETE', $IcingaUser));
+    $UserConfig = Get-IcingaWindowsInformation -Class 'Win32_UserAccount' -Filter ([string]::Format("SID = '{0}'", $SID));
+    $Result     = Start-IcingaProcess -Executable 'net' -Arguments ([string]::Format('user "{0}" /DELETE', $UserConfig.Name));
 
     if ($Result.ExitCode -ne 0) {
         Write-IcingaConsoleError 'Failed to delete user "{0}": {1}' -Objects $IcingaUser, $Result.Error;
     } else {
         # Delete Home Directory
         $HomePath = Join-Path -Path ($ENV:HOMEDRIVE) -ChildPath (Join-Path -Path '\Users\' -ChildPath $IcingaUser);
-        Remove-ItemSecure -Path $HomePath -Recurse -Force;
+        Remove-ItemSecure -Path $HomePath -Recurse -Force | Out-Null;
     }
 
     return @{
diff --git a/lib/core/windows/Test-IcingaManagedUser.psm1 b/lib/core/windows/Test-IcingaManagedUser.psm1
index 4a174d9..c33b65c 100644
--- a/lib/core/windows/Test-IcingaManagedUser.psm1
+++ b/lib/core/windows/Test-IcingaManagedUser.psm1
@@ -5,18 +5,15 @@ function Test-IcingaManagedUser()
         [string]$SID
     );
 
-    $UserData     = Get-IcingaWindowsInformation -Class 'Win32_UserAccount' | Where-Object { $_.Name -eq $IcingaUser };
-    $FullUserData = Get-IcingaWindowsInformation -Class 'Win32_UserAccount' | Where-Object { $_.Caption.ToLower() -eq $IcingaUser.ToLower() };
-
-    if ($null -eq $FullUserData -And $null -eq $UserData -And [string]::IsNullOrEmpty($SID)) {
-        return $FALSE;
-    }
-
     if ([string]::IsNullOrEmpty($SID)) {
         $SID = Get-IcingaUserSID -User $IcingaUser;
     }
 
-    $UserConfig   = Get-IcingaWindowsInformation -Class 'Win32_UserAccount' | Where-Object { $_.SID -eq $SID };
+    if ([string]::IsNullOrEmpty($SID)) {
+        return $FALSE;
+    }
+
+    $UserConfig   = Get-IcingaWindowsInformation -Class 'Win32_UserAccount' -Filter ([string]::Format("SID = '{0}'", $SID));
     $UserMetadata = Get-IcingaWindowsUserMetadata;
 
     if ($null -eq $UserConfig -Or $UserConfig.FullName -ne $UserMetadata.FullName -Or $UserConfig.Description -ne $UserMetadata.Description) {
diff --git a/lib/core/windows/Update-IcingaServiceUser.psm1 b/lib/core/windows/Update-IcingaServiceUser.psm1
index e62b90b..c4495c8 100644
--- a/lib/core/windows/Update-IcingaServiceUser.psm1
+++ b/lib/core/windows/Update-IcingaServiceUser.psm1
@@ -11,7 +11,7 @@ function Update-IcingaServiceUser()
     }
 
     $SID          = Get-IcingaUserSID -User $IcingaUser;
-    $UserConfig   = Get-IcingaWindowsInformation -Class 'Win32_UserAccount' | Where-Object { $_.SID -eq $SID };
+    $UserConfig   = Get-IcingaWindowsInformation -Class 'Win32_UserAccount' -Filter ([string]::Format("SID = '{0}'", $SID));
     $User         = New-IcingaWindowsUser -IcingaUser $UserConfig.Name;
 
     Set-IcingaServiceUser -User $IcingaUser -Password $Global:Icinga.ServiceUserPassword -Service 'icinga2' | Out-Null;