diff --git a/CHANGELOG.md b/CHANGELOG.md
index b1c5e898..4f6336b5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+- `ComputerManagementDsc`
+  - Updated unit tests for Pester 6 compatibility - replaced the removed
+    `Assert-MockCalled` with `Should -Invoke`, and moved a data-driven test's
+    `$testCases` into `BeforeDiscovery` so `-ForEach` is populated at discovery
+    time (Pester 6 throws on a `$null`/empty `-ForEach`).
 - `azure-pipelines.yml`
   - Remove `windows-2019` images fixes [#451](https://github.com/dsccommunity/ComputerManagementDsc/issues/451).
 - Module manifest: Set `CmdletsToExport` to `'*'` to satisfy HQRM tests.
diff --git a/RequiredModules.psd1 b/RequiredModules.psd1
index 792fc0b0..67843b83 100644
--- a/RequiredModules.psd1
+++ b/RequiredModules.psd1
@@ -9,7 +9,10 @@
 
     InvokeBuild                 = 'latest'
     PSScriptAnalyzer            = 'latest'
-    Pester                      = 'latest'
+    Pester                      = @{
+        Version    = '6.0.0-rc2'
+        Parameters = @{ AllowPrerelease = $true }
+    }
     Plaster                     = 'latest'
     ModuleBuilder               = 'latest'
     ChangelogManagement         = 'latest'
diff --git a/tests/Integration/ComputerManagementDsc.Common.Tests.ps1 b/tests/Integration/ComputerManagementDsc.Common.Tests.ps1
index 4baf3e5f..9ae46bdc 100644
--- a/tests/Integration/ComputerManagementDsc.Common.Tests.ps1
+++ b/tests/Integration/ComputerManagementDsc.Common.Tests.ps1
@@ -81,6 +81,12 @@ Describe 'ComputerManagementDsc.Common\Set-TimeZoneId' {
     #>
     Context '''Set-TimeZone'' is not available but ''Add-Type'' is available' {
         BeforeAll {
+            # Pester v6 throws instead of calling the real command when a mock has only
+            # -ParameterFilter behaviours and none match. Forward unmatched Get-Command
+            # calls (e.g. the 'Get-TimeZone' lookup in Get-TimeZoneId) to the real cmdlet
+            # to keep the v5 fall-through behaviour.
+            Mock -CommandName Get-Command -MockWith { & (Get-Command -Name 'Get-Command' -CommandType Cmdlet) @PesterBoundParameters }
+
             Mock -CommandName Get-Command -ParameterFilter {
                 $Name -eq 'Add-Type'
             } -MockWith { 'Add-Type' }
diff --git a/tests/Unit/DSC_Computer.Tests.ps1 b/tests/Unit/DSC_Computer.Tests.ps1
index 0b5ca585..3cc84f4b 100644
--- a/tests/Unit/DSC_Computer.Tests.ps1
+++ b/tests/Unit/DSC_Computer.Tests.ps1
@@ -676,7 +676,7 @@ Describe 'DSC_Computer\Test-TargetResource' {
             }
         }
 
-        BeforeEach {
+        BeforeDiscovery {
             $testCases = @(
                 @{ Name = $env:COMPUTERNAME }
                 @{ Name = 'localhost' }
diff --git a/tests/Unit/DSC_SystemProtection.Tests.ps1 b/tests/Unit/DSC_SystemProtection.Tests.ps1
index 862f784c..0f2765af 100644
--- a/tests/Unit/DSC_SystemProtection.Tests.ps1
+++ b/tests/Unit/DSC_SystemProtection.Tests.ps1
@@ -135,7 +135,7 @@ Describe "DSC_SystemProtection\Get-TargetResource" -Tag 'Get' {
                     $protectionSettings = Get-TargetResource -Ensure 'Present' -DriveLetter 'C'
 
                     $protectionSettings.Ensure | Should -Be 'Absent'
-                    Assert-MockCalled -CommandName Write-Warning -Times 1
+                    Should -Invoke -CommandName Write-Warning -Times 1
                 }
             }
         }
@@ -263,7 +263,7 @@ Describe "DSC_SystemProtection\Test-TargetResource" -Tag 'Test' {
                 $desiredState = Test-TargetResource -Ensure 'Present' -DriveLetter 'C'
 
                 $desiredState | Should -BeTrue
-                Assert-MockCalled -CommandName Write-Warning -Times 2
+                Should -Invoke -CommandName Write-Warning -Times 2
             }
         }
     }
@@ -357,7 +357,7 @@ Describe "DSC_SystemProtection\Set-TargetResource" -Tag 'Set' {
 
                     Set-TargetResource -Ensure 'Present' -DriveLetter 'P'
 
-                    Assert-MockCalled -CommandName Enable-ComputerRestore -Times 1
+                    Should -Invoke -CommandName Enable-ComputerRestore -Times 1
                 }
             }
 
@@ -369,7 +369,7 @@ Describe "DSC_SystemProtection\Set-TargetResource" -Tag 'Set' {
 
                     Set-TargetResource -Ensure 'Absent' -DriveLetter 'P'
 
-                    Assert-MockCalled -CommandName Disable-ComputerRestore
+                    Should -Invoke -CommandName Disable-ComputerRestore
                 }
             }
 
@@ -382,8 +382,8 @@ Describe "DSC_SystemProtection\Set-TargetResource" -Tag 'Set' {
 
                     Set-TargetResource -Ensure 'Present' -DriveLetter 'P' -DiskUsage 20
 
-                    Assert-MockCalled -CommandName Enable-ComputerRestore -Times 1
-                    Assert-MockCalled -CommandName Invoke-VssAdmin -Times 1
+                    Should -Invoke -CommandName Enable-ComputerRestore -Times 1
+                    Should -Invoke -CommandName Invoke-VssAdmin -Times 1
                 }
             }
 
@@ -425,10 +425,10 @@ Describe "DSC_SystemProtection\Set-TargetResource" -Tag 'Set' {
 
                     Set-TargetResource -Ensure  'Present' -DriveLetter 'P' -DiskUsage 1 -Force $true
 
-                    Assert-MockCalled -CommandName Enable-ComputerRestore -Times 1
-                    Assert-MockCalled -CommandName Invoke-VssAdmin -ParameterFilter { $Operation -eq 'Resize' } -Times 2
-                    Assert-MockCalled -CommandName Invoke-VssAdmin -ParameterFilter { $Operation -eq 'Delete' } -Times 1
-                    Assert-MockCalled -CommandName Write-Warning -Times 1
+                    Should -Invoke -CommandName Enable-ComputerRestore -Times 1
+                    Should -Invoke -CommandName Invoke-VssAdmin -ParameterFilter { $Operation -eq 'Resize' } -Times 2
+                    Should -Invoke -CommandName Invoke-VssAdmin -ParameterFilter { $Operation -eq 'Delete' } -Times 1
+                    Should -Invoke -CommandName Write-Warning -Times 1
                 }
             }
 
diff --git a/tests/Unit/DSC_SystemRestorePoint.Tests.ps1 b/tests/Unit/DSC_SystemRestorePoint.Tests.ps1
index ecdf06fc..bdb36a1d 100644
--- a/tests/Unit/DSC_SystemRestorePoint.Tests.ps1
+++ b/tests/Unit/DSC_SystemRestorePoint.Tests.ps1
@@ -113,7 +113,7 @@ Describe "DSC_SystemRestorePoint\Get-TargetResource" -Tag 'Get' {
                 $protectionSettings = Get-TargetResource -Ensure 'Present' -Description 'DSC Unit Test'
 
                 $protectionSettings.Ensure | Should -Be 'Absent'
-                Assert-MockCalled -CommandName Write-Warning -Times 1
+                Should -Invoke -CommandName Write-Warning -Times 1
             }
         }
     }
@@ -201,7 +201,7 @@ Describe "DSC_SystemRestorePoint\Test-TargetResource" -Tag 'Test' {
                 $desiredState = Test-TargetResource -Ensure 'Present' -Description 'DSC Unit Test'
 
                 $desiredState | Should -BeTrue
-                Assert-MockCalled -CommandName Write-Warning -Times 2
+                Should -Invoke -CommandName Write-Warning -Times 2
             }
         }
     }