diff --git a/changelog.md b/changelog.md
index 0b6b8ee..78c21ef 100644
--- a/changelog.md
+++ b/changelog.md
@@ -4,6 +4,12 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
+## [Unreleased]
+### Added
+* `Test-AdfCode` warns about enabled triggers without pipeline references, which ADF refuses to start #507
+### Fixed
+* Starting and stopping triggers now catches Az errors whatever `$ErrorActionPreference` is, so retries and warnings work; a failed start is a warning and the deployment carries on #508
+
 ## [1.19.0] - 2026-10-16
 ### Added
 * Stopping a trigger now retries up to 5 times (and waits while the trigger is provisioning), like starting a trigger #404
diff --git a/docs/FEATURES/BUILD_AND_TEST.md b/docs/FEATURES/BUILD_AND_TEST.md
index 0e0322f..24083a3 100644
--- a/docs/FEATURES/BUILD_AND_TEST.md
+++ b/docs/FEATURES/BUILD_AND_TEST.md
@@ -63,7 +63,16 @@ ERROR: Pipeline 'PL_CopyData' references dataset 'DS_Missing' which does not exi
 ERROR: File 'pipeline\PL_Copy.json' contains object named 'PL_CopyData' (name mismatch)
 ```
 
-### 4. Additional Checks
+### 4. Trigger Validation
+- Warns about enabled triggers (`runtimeState: Started`) without pipeline references
+- Azure Data Factory refuses to start such triggers, so the deployment would only report the API error `Missing or invalid pipeline references`
+
+**Warning Example:**
+```
+WARNING: Trigger 'TR_Daily' is enabled (runtimeState: Started) but has no pipeline references. Azure Data Factory will fail to start it.
+```
+
+### 5. Additional Checks
 - More validations coming soon...
 
 ## Using Test-AdfCode in CI/CD
diff --git a/private/Start-Trigger.ps1 b/private/Start-Trigger.ps1
index 8cd37ee..60f1e6f 100644
--- a/private/Start-Trigger.ps1
+++ b/private/Start-Trigger.ps1
@@ -1,5 +1,6 @@
 function Start-Trigger {
     [CmdletBinding()]
+    [OutputType([bool])]
     param (
         [parameter(Mandatory = $true)] [string] $ResourceGroupName,
         [parameter(Mandatory = $true)] [string] $DataFactoryName,
@@ -10,20 +11,29 @@ function Start-Trigger {
     Write-Host "- Enabling trigger: $Name"
     $attempts = 5;
     $i = 0
+    $started = $false
     while ($i -lt $attempts)
     {
         $i++
         try {
+            # Az cmdlets write non-terminating errors, so -ErrorAction Stop is required to catch them
             Start-AzDataFactoryV2Trigger `
                 -ResourceGroupName $ResourceGroupName `
                 -DataFactoryName $DataFactoryName `
                 -Name $Name `
-                -Force | Out-Null
+                -Force -ErrorAction Stop | Out-Null
             # If successful, break out of the loop
+            $started = $true
             break
         }
         catch {
             $errMsg = $_.Exception.Message
+            if ($errMsg -like "*Missing or invalid pipeline references*") {
+                # Permanent error - retry won't help (see Test-AdfCode)
+                Write-Host "Failed starting trigger."
+                Write-Warning -Message $errMsg
+                break
+            }
             if ($i -lt $attempts)
             {
                 if ($errMsg -like "*cannot be updated during provisioning*") {
@@ -56,4 +66,5 @@ function Start-Trigger {
     }
 
     Write-Debug "END: Start-Trigger()"
+    return $started
 }
diff --git a/private/Start-Triggers.ps1 b/private/Start-Triggers.ps1
index 7adedf9..386d223 100644
--- a/private/Start-Triggers.ps1
+++ b/private/Start-Triggers.ps1
@@ -50,12 +50,21 @@ function Start-Triggers {
     if ($toBeStarted.Count -gt 0)
     {
         Write-Host "Starting triggers:"
-        $toBeStarted | ForEach-Object { 
-            Start-Trigger `
+        [System.Collections.ArrayList] $failedToStart = @{}
+        $toBeStarted | ForEach-Object {
+            $TrName = $_
+            $isStarted = Start-Trigger `
             -ResourceGroupName $adf.ResourceGroupName `
             -DataFactoryName $adf.Name `
-            -Name $_ `
-            | Out-Null
+            -Name $TrName
+
+            if (-not $isStarted) {
+                $failedToStart.Add($TrName) | Out-Null
+            }
+        }
+        # Deployment carries on: a failed start is reported as a warning only
+        if ($failedToStart.Count -gt 0) {
+            Write-Warning "The number of triggers that failed to start: $($failedToStart.Count) ($($failedToStart -join ', '))"
         }
         Write-Host "Complete starting triggers."
     }
diff --git a/private/Stop-Trigger.ps1 b/private/Stop-Trigger.ps1
index 33dcc80..d6b2ba9 100644
--- a/private/Stop-Trigger.ps1
+++ b/private/Stop-Trigger.ps1
@@ -16,11 +16,12 @@ function Stop-Trigger {
     {
         $i++
         try {
+            # Az cmdlets write non-terminating errors, so -ErrorAction Stop is required to catch them
             Stop-AzDataFactoryV2Trigger `
                 -ResourceGroupName $ResourceGroupName `
                 -DataFactoryName $DataFactoryName `
                 -Name $Name `
-                -Force | Out-Null
+                -Force -ErrorAction Stop | Out-Null
             # If successful, break out of the loop
             $stopped = $true
             break
diff --git a/public/Test-AdfCode.ps1 b/public/Test-AdfCode.ps1
index f1dbcb1..d14a571 100644
--- a/public/Test-AdfCode.ps1
+++ b/public/Test-AdfCode.ps1
@@ -99,6 +99,21 @@ function Test-AdfCode {
         }
     }
 
+    Write-Host "Checking enabled triggers have pipeline references..."
+    $adf.Triggers | ForEach-Object {
+        $props = $_.Body.properties
+        $propNames = $props.PSObject.Properties.Name
+        if ('runtimeState' -in $propNames -and $props.runtimeState -eq 'Started') {
+            # TumblingWindowTrigger uses a single 'pipeline', other trigger types use a 'pipelines' array
+            $pipelines = @(if ('pipelines' -in $propNames) { $props.pipelines | Where-Object { $_ } })
+            $hasPipeline = $pipelines.Count -gt 0 -or ('pipeline' -in $propNames -and $null -ne $props.pipeline)
+            if (-not $hasPipeline) {
+                Write-Warning "Trigger '$($_.Name)' is enabled (runtimeState: Started) but has no pipeline references. Azure Data Factory will fail to start it."
+                $result.WarningCount += 1
+            }
+        }
+    }
+
     Write-Host "Checking: Global parameter names..."
     if ($adf.Factories.Count -gt 0) {
         $gparams = $adf.GlobalFactory.GlobalParameters
diff --git a/test/Start-Trigger.Tests.ps1 b/test/Start-Trigger.Tests.ps1
index f14a7a6..d693b1f 100644
--- a/test/Start-Trigger.Tests.ps1
+++ b/test/Start-Trigger.Tests.ps1
@@ -57,6 +57,74 @@ InModuleScope azure.datafactory.tools {
         }
 
     }
+
+    # Az cmdlets report failures as non-terminating errors (they do not throw) #508
+    Describe 'Start-Trigger when Az cmdlet writes a non-terminating error #508' -Tag 'Unit' {
+
+        BeforeEach {
+            $ErrorActionPreference = 'Continue'     # default preference, as in most pipelines
+            Mock Start-Sleep {}
+            Mock Write-Warning {}
+        }
+
+        It 'Should return true when started' {
+            Mock Start-AzDataFactoryV2Trigger { }
+            Start-Trigger -ResourceGroupName 'rg' -DataFactoryName 'adf' -Name 'tr1' | Should -BeTrue
+            Should -Invoke Start-AzDataFactoryV2Trigger -Times 1 -Exactly
+        }
+
+        It 'Should retry a transient error, then warn and return false' {
+            Mock Start-AzDataFactoryV2Trigger { Write-Error 'Conflict: There are concurrent operations on the trigger' }
+            Start-Trigger -ResourceGroupName 'rg' -DataFactoryName 'adf' -Name 'tr1' | Should -BeFalse
+            Should -Invoke Start-AzDataFactoryV2Trigger -Times 5 -Exactly
+            Should -Invoke Write-Warning -Times 1 -Exactly -ParameterFilter { $Message -like '*concurrent operations*' }
+        }
+
+        It 'Should succeed when a retry works' {
+            $script:startAttempt = 0
+            Mock Start-AzDataFactoryV2Trigger { $script:startAttempt++; if ($script:startAttempt -eq 1) { Write-Error 'Conflict: concurrent operations' } }
+            Start-Trigger -ResourceGroupName 'rg' -DataFactoryName 'adf' -Name 'tr1' | Should -BeTrue
+            Should -Invoke Start-AzDataFactoryV2Trigger -Times 2 -Exactly
+            Should -Invoke Write-Warning -Times 0 -Exactly
+        }
+
+        It 'Should not retry a permanent error (missing pipeline references)' {
+            Mock Start-AzDataFactoryV2Trigger { Write-Error 'HTTP Status Code: BadRequest Error Code: BadRequest Error Message: Missing or invalid pipeline references for trigger tr1' }
+            Start-Trigger -ResourceGroupName 'rg' -DataFactoryName 'adf' -Name 'tr1' | Should -BeFalse
+            Should -Invoke Start-AzDataFactoryV2Trigger -Times 1 -Exactly
+            Should -Invoke Write-Warning -Times 1 -Exactly -ParameterFilter { $Message -like '*Missing or invalid pipeline references*' }
+        }
+
+        It 'Should not write the error to the error stream' {
+            Mock Start-AzDataFactoryV2Trigger { Write-Error 'Missing or invalid pipeline references for trigger tr1' }
+            $out = Start-Trigger -ResourceGroupName 'rg' -DataFactoryName 'adf' -Name 'tr1' 2>&1
+            @($out | Where-Object { $_ -is [System.Management.Automation.ErrorRecord] }) | Should -BeNullOrEmpty
+        }
+    }
+
+    Describe 'Start-Triggers when a trigger fails to start #508' -Tag 'Unit' {
+
+        BeforeAll {
+            Mock Start-Trigger { param ($ResourceGroupName, $DataFactoryName, $Name) return ($Name -ne 'tr2') }
+            Mock Write-Warning {}
+
+            $script:adf = [Adf]::new()
+            $script:adf.Name = 'adf'
+            $script:adf.ResourceGroupName = 'rg'
+            $script:adf.PublishOptions = New-AdfPublishOption
+            foreach ($n in 'tr1', 'tr2', 'tr3') {
+                $script:adf.Triggers.Add([PSCustomObject]@{ Name = $n; Body = [PSCustomObject]@{ properties = [PSCustomObject]@{ runtimeState = 'Started' } } }) | Out-Null
+            }
+        }
+
+        It 'Should carry on (not throw) and try to start all triggers' {
+            { Start-Triggers -adf $script:adf } | Should -Not -Throw
+            Should -Invoke Start-Trigger -Times 3 -Exactly
+        }
+        It 'Should warn about triggers which failed to start' {
+            Should -Invoke Write-Warning -Times 1 -Exactly -Scope Describe -ParameterFilter { $Message -like '*tr2*' -and $Message -notlike '*tr1*' -and $Message -notlike '*tr3*' }
+        }
+    }
 }
 
 
diff --git a/test/Stop-Trigger.Tests.ps1 b/test/Stop-Trigger.Tests.ps1
index 6f597f4..b7808b2 100644
--- a/test/Stop-Trigger.Tests.ps1
+++ b/test/Stop-Trigger.Tests.ps1
@@ -67,6 +67,36 @@ InModuleScope azure.datafactory.tools {
         }
     }
 
+    # Az cmdlets report failures as non-terminating errors (they do not throw) #508
+    Describe 'Stop-Trigger when Az cmdlet writes a non-terminating error #508' -Tag 'Unit' {
+
+        BeforeEach {
+            $ErrorActionPreference = 'Continue'     # default preference, as in most pipelines
+            Mock Start-Sleep {}
+            Mock Write-Warning {}
+        }
+
+        It 'Should retry a transient error, then warn and return false' {
+            Mock Stop-AzDataFactoryV2Trigger { Write-Error 'Conflict: There are concurrent operations on the trigger' }
+            Stop-Trigger -ResourceGroupName 'rg' -DataFactoryName 'adf' -Name 'tr1' | Should -BeFalse
+            Should -Invoke Stop-AzDataFactoryV2Trigger -Times 5 -Exactly
+            Should -Invoke Write-Warning -Times 1 -Exactly -ParameterFilter { $Message -like '*concurrent operations*' }
+        }
+
+        It 'Should succeed when a retry works' {
+            $script:stopAttempt = 0
+            Mock Stop-AzDataFactoryV2Trigger { $script:stopAttempt++; if ($script:stopAttempt -eq 1) { Write-Error 'Conflict: concurrent operations' } }
+            Stop-Trigger -ResourceGroupName 'rg' -DataFactoryName 'adf' -Name 'tr1' | Should -BeTrue
+            Should -Invoke Stop-AzDataFactoryV2Trigger -Times 2 -Exactly
+        }
+
+        It 'Should not write the error to the error stream' {
+            Mock Stop-AzDataFactoryV2Trigger { Write-Error 'Conflict: concurrent operations' }
+            $out = Stop-Trigger -ResourceGroupName 'rg' -DataFactoryName 'adf' -Name 'tr1' 2>&1
+            @($out | Where-Object { $_ -is [System.Management.Automation.ErrorRecord] }) | Should -BeNullOrEmpty
+        }
+    }
+
     Describe 'Stop-Triggers when a trigger fails to stop' -Tag 'Unit' {
 
         BeforeAll {
diff --git a/test/Test-AdfCode.Tests.ps1 b/test/Test-AdfCode.Tests.ps1
index dcdda36..04728f1 100644
--- a/test/Test-AdfCode.Tests.ps1
+++ b/test/Test-AdfCode.Tests.ps1
@@ -76,6 +76,51 @@ InModuleScope azure.datafactory.tools {
         }
     }
 
+    Describe 'Test-AdfCode trigger without pipeline references #507' -Tag 'Unit' {
+        BeforeEach {
+            Mock Write-Warning {}
+        }
+
+        It 'Should warn about enabled trigger TR_without_pipeline in adf2' {
+            $RootFolder = Join-Path -Path $PSScriptRoot -ChildPath 'adf2'
+            $script:res = Test-AdfCode -RootFolder $RootFolder
+            Should -Invoke Write-Warning -Times 1 -Exactly -ParameterFilter { $Message -like '*TR_without_pipeline*' }
+        }
+
+        It 'Should return 0 errors and 1 warning for adf2' {
+            $script:res.ErrorCount | Should -Be 0
+            $script:res.WarningCount | Should -Be 1
+        }
+
+        It 'Should <expected> for <type> with runtimeState <state> (<case>)' -ForEach @(
+            @{ case = 'empty pipelines';       type = 'ScheduleTrigger';       state = 'Started'; prop = 'pipelines'; refs = $false; expected = 'warn' }
+            @{ case = 'no pipelines property'; type = 'ScheduleTrigger';       state = 'Started'; prop = $null;       refs = $false; expected = 'warn' }
+            @{ case = 'empty pipelines';       type = 'BlobEventsTrigger';     state = 'Started'; prop = 'pipelines'; refs = $false; expected = 'warn' }
+            @{ case = 'no pipeline property';  type = 'TumblingWindowTrigger'; state = 'Started'; prop = $null;       refs = $false; expected = 'warn' }
+            @{ case = 'with pipeline';         type = 'ScheduleTrigger';       state = 'Started'; prop = 'pipelines'; refs = $true;  expected = 'not warn' }
+            @{ case = 'with pipeline';         type = 'TumblingWindowTrigger'; state = 'Started'; prop = 'pipeline';  refs = $true;  expected = 'not warn' }
+            @{ case = 'empty pipelines';       type = 'ScheduleTrigger';       state = 'Stopped'; prop = 'pipelines'; refs = $false; expected = 'not warn' }
+            @{ case = 'no pipeline property';  type = 'TumblingWindowTrigger'; state = 'Stopped'; prop = $null;       refs = $false; expected = 'not warn' }
+        ) {
+            $RootFolder = Join-Path -Path $TestDrive -ChildPath "adf435-$([guid]::NewGuid().ToString('N').Substring(0,8))"
+            New-Item -ItemType Directory -Path "$RootFolder/trigger", "$RootFolder/pipeline" -Force | Out-Null
+            '{ "name": "PL_Wait", "properties": { "activities": [] } }' | Set-Content "$RootFolder/pipeline/PL_Wait.json"
+
+            $pipelineRef = @{ pipelineReference = @{ referenceName = 'PL_Wait'; type = 'PipelineReference' } }
+            $properties = [ordered]@{ runtimeState = $state; type = $type; typeProperties = @{} }
+            switch ($prop) {
+                'pipelines' { $properties.pipelines = if ($refs) { @($pipelineRef) } else { @() } }
+                'pipeline'  { $properties.pipeline = $pipelineRef }
+            }
+            @{ name = 'TR_Test'; properties = $properties } | ConvertTo-Json -Depth 10 | Set-Content "$RootFolder/trigger/TR_Test.json"
+
+            Test-AdfCode -RootFolder $RootFolder | Out-Null
+
+            $times = if ($expected -eq 'warn') { 1 } else { 0 }
+            Should -Invoke Write-Warning -Times $times -Exactly -ParameterFilter { $Message -like '*TR_Test*' }
+        }
+    }
+
     Describe 'Test-AdfCode' -Tag 'Unit' {
         It 'Should not throw an error when Get-ChildItem Path parameter is null' {
             $DataFactoryName = "adf2"
diff --git a/test/Triggers.Tests.ps1 b/test/Triggers.Tests.ps1
index 1f940fd..b98acbb 100644
--- a/test/Triggers.Tests.ps1
+++ b/test/Triggers.Tests.ps1
@@ -46,6 +46,7 @@ InModuleScope azure.datafactory.tools {
             $o = $script:TargetAdf.GetObjectByFullName("*triggers.$Name")
             $o.RuntimeState = 'Started'
             $o.Body.properties.RuntimeState = $o.RuntimeState
+            return $true
         }
         Mock Stop-TargetTrigger {
             param ($Name, $ResourceGroupName, $DataFactoryName)