High Packer.exe CPU load during Build - Builds don't finish anymore

#### Community Note * Please vote on this issue by adding a [reaction](https://blog.github.com/2016-03-10-add-reactions-to-pull-requests-issues-and-comments/) to the original issue to help the community and maintainers prioritize this request * Please do not leave "+1" or other comments that do not add relevant new information or questions, they generate extra noise for issue followers and do not help prioritize the request * If you are interested in working on this issue or have submitted a pull request, please leave a comment When filing a bug, please include the following headings if possible. Any example text in this template can be deleted. #### Overview of the Issue Since about mid-august 2025, the Packer.exe on my Windows 2019 Build Server, which is orchestrated by Azure DevOps, to Build Citrix DaaS Master Images, has an extremly high load. This server does Packer builds since 01/2022 and the issues started only a few weeks ago. I suspect this is the reason that all my builds fail and don't finis anymore. #### Reproduction Steps I create a Windows 11 23H2 Multi User Master Image for Citrix DaaS an Azure West Europe. ### Packer version Packer v1.14.2 ### Simplified Packer Template Details

packer { required_plugins { azure = { version = ">= 2.5.0" source = "github.com/hashicorp/azure" } windows-update = { version = ">= 0.17.1" source = "github.com/rgl/windows-update" } } } source "azure-arm" "win11-23h2-avd" { azure_tags = { "Created by" = "ANX-IT/MHN" "Environment" = "Prod" } skip_create_image = true async_resourcegroup_delete = true subscription_id = "${var.azure_subscription_id}" client_id = "${var.azure_client_id}" client_secret = "${var.azure_client_secret}" build_resource_group_name = "rg-pur-packer-build" os_type = "Windows" image_publisher = "MicrosoftWindowsDesktop" image_offer = "Windows-11" image_sku = "win11-23h2-avd" vm_size = "Standard_NC8as_T4_v3" polling_duration_timeout = "30m" virtual_network_resource_group_name = "rg-pur-network" virtual_network_name = "vnet-pur-main" virtual_network_subnet_name = "subnet-pur-citrix" communicator = "winrm" winrm_insecure = true winrm_timeout = "5m" winrm_use_ssl = true winrm_username = "packer" managed_image_name = "packer-win11-23h2-avd" managed_image_os_disk_snapshot_name = "${var.snapshotname}" managed_image_resource_group_name = "rg-pur-packer-images" managed_image_storage_account_type = "Premium_LRS" os_disk_size_gb = "200" } build { sources = ["source.azure-arm.win11-23h2-avd"] provisioner "powershell" { use_pwsh = false inline = [ "while ((Get-Service RdAgent -ErrorAction SilentlyContinue).Status -ne 'Running') { Start-Sleep -s 5 }", "while ((Get-Service WindowsAzureGuestAgent -ErrorAction SilentlyContinue).Status -ne 'Running') { Start-Sleep -s 5 }", "Set-ExecutionPolicy Bypass -Scope Process -Force" ] } provisioner "powershell" { use_pwsh = false environment_vars = [ "downloadcache=${var.downloadcache}", "localuser=${var.localuser}", "localuserpw=${var.localuserpw}" ] scripts = [ "scripts/001_preparation.ps1", "scripts/002_PowerShell-x64.ps1" ] } provisioner "powershell" { use_pwsh = true script = "scripts/003_pwsh-modules.ps1" } provisioner "windows-restart" { restart_timeout = "10m" } provisioner "powershell" { use_pwsh = false script = "scripts/010_language-de-DE.ps1" } provisioner "windows-update" { pause_before = "1m" restart_timeout = "15m" search_criteria = "IsInstalled=0" filters = [ "exclude:$_.Title -like '*Silverlight*'", "exclude:$_.Title -like '*Preview*'", "exclude:$_.Title -like '*Vorschau*'", "exclude:$_.Title -like '*KB5040442*'", "include:$true" ] update_limit = 25 } provisioner "windows-restart" { restart_timeout = "15m" } provisioner "powershell" { use_pwsh = true script = "scripts/osbuild.ps1" } provisioner "powershell" { use_pwsh = false script = "scripts/015_VcRedist.ps1" } provisioner "powershell" { use_pwsh = true environment_vars = [ "storageaccountname=${var.storageaccountname}", "storageaccountcontainer=${var.storageaccountcontainer}", "storagecontainerkey=${var.storagecontainerkey}", "downloadcache=${var.downloadcache}" ] scripts = [ "scripts/107_Microsoft-NET-LTS.ps1", "scripts/108_Microsoft-Sysinternals-PsTools-Suite.ps1", "scripts/109_Microsoft-OLE-DB-Driver-for-SQL-Server.ps1", "scripts/110_Microsoft-ODBC-Driver-for-SQL-Server.ps1" ] } provisioner "windows-restart" { restart_timeout = "15m" } provisioner "powershell" { use_pwsh = true environment_vars = [ "storageaccountname=${var.storageaccountname}", "storageaccountcontainer=${var.storageaccountcontainer}", "storagecontainerkey=${var.storagecontainerkey}", "downloadcache=${var.downloadcache}" ] script = "scripts/020_nvidia.ps1" } provisioner "windows-restart" { restart_timeout = "15m" } provisioner "powershell" { use_pwsh = true environment_vars = [ "storageaccountname=${var.storageaccountname}", "storageaccountcontainer=${var.storageaccountcontainer}", "storagecontainerkey=${var.storagecontainerkey}", "downloadcache=${var.downloadcache}", "localuser=${var.localuser}" ] scripts = [ "scripts/030_Citrix-VDA.ps1", "scripts/039_RDAnalyzer.ps1", "scripts/040_FSLogix-Apps.ps1", "scripts/042_Citrix-WEM-Agent.ps1", "scripts/045_Zabbix agent.ps1", "scripts/050_BIS-F.ps1", "scripts/051_Citrix-Optimizer.ps1", "scripts/052_delprof2.ps1" ] } provisioner "windows-restart" { restart_timeout = "15m" } provisioner "powershell" { use_pwsh = true environment_vars = [ "storageaccountname=${var.storageaccountname}", "storageaccountcontainer=${var.storageaccountcontainer}", "storagecontainerkey=${var.storagecontainerkey}", "downloadcache=${var.downloadcache}" ] scripts = [ "scripts/100_Microsoft-Office365.ps1", "scripts/102_Microsoft-Teams2.ps1", "scripts/103_Microsoft-OneDrive.ps1", "scripts/104_Microsoft-SSMS.ps1", "scripts/105_Microsoft-VSCode.ps1", "scripts/106_Microsoft-Azure-Storage-Explorer.ps1", "scripts/112_Notepad-PlusPlus.ps1", "scripts/113_AdobeAcrobatReaderDC.ps1", "scripts/115_Mozilla-Firefox.ps1", "scripts/116_VideoLanVlcPlayer.ps1", "scripts/121_PDF24.ps1", "scripts/122_PaintNET.ps1", "scripts/124_Greenshot.ps1", "scripts/125_ImageGlass.ps1" ] } provisioner "powershell" { use_pwsh = true elevated_user = "${var.localuser}" elevated_password = "${var.localuserpw}" environment_vars = [ "pdquser=${var.pdquser}", "pdquserpw=${var.pdquserpw}" ] scripts = [ "scripts/PDQ.ps1" ] } provisioner "powershell" { use_pwsh = true elevated_user = "${var.localuser}" elevated_password = "${var.localuserpw}" environment_vars = [ "storageaccountname=${var.storageaccountname}", "storageaccountcontainer=${var.storageaccountcontainer}", "storagecontainerkey=${var.storagecontainerkey}", "downloadcache=${var.downloadcache}" ] scripts = [ "scripts/201_AutoCAD.ps1", "scripts/201_AutoCAD-EN.ps1", "scripts/201_JS_Menu.ps1", "scripts/201_Loopback.ps1", "scripts/210_Autodesk-Navisworks-Freedom-2024-Update-2.ps1", "scripts/203_3DxWare.ps1", "scripts/204_BricsCAD.ps1", "scripts/205_Druckverlust.ps1", "scripts/206_ELiA.ps1", "scripts/207_ProjektPro.ps1", "scripts/208_RedBag.ps1", "scripts/ROHR2.viewer.ps1", "scripts/CONVAL.ps1", "scripts/Microsoft_Edge.ps1", "scripts/Citrix-Workspace-app.ps1", "scripts/Datev-Sicherheitspaket-compact.ps1" ] } provisioner "windows-restart" { restart_timeout = "60m" } provisioner "windows-update" { pause_before = "1m" restart_timeout = "60m" search_criteria = "IsInstalled=0" filters = [ "exclude:$_.Title -like '*Silverlight*'", "exclude:$_.Title -like '*Preview*'", "exclude:$_.Title -like '*Vorschau*'", "include:$true" ] update_limit = 25 } provisioner "windows-restart" { restart_timeout = "60m" } provisioner "file" { direction = "upload" sources = [ "pester/pur-daas.Tests.ps1", "pester/MachineBuild-Config.psd1", "pester/Test-MachineBuild.Tests.ps1" ] destination = "${var.downloadcache}/" } provisioner "powershell" { use_pwsh = true environment_vars = ["downloadcache=${var.downloadcache}"] scripts = [ "pester/Invoke-Pester.ps1", "scripts/991_Get-Installed.ps1" ] } provisioner "file" { direction = "download" source = "${var.downloadcache}/testResults.xml" destination = "pester/testResults.xml" } provisioner "file" { direction = "download" source = "${var.downloadcache}/InstalledSoftware.txt" destination = "./InstalledSoftware.txt" } provisioner "powershell" { use_pwsh = true environment_vars = ["downloadcache=${var.downloadcache}"] script = "pester/Get-TestResults.ps1" } provisioner "powershell" { use_pwsh = true environment_vars = ["downloadcache=${var.downloadcache}"] inline = [ "Write-Verbose 'Remove download cache' -Verbose", "Remove-Item -Path $env:downloadcache -Recurse -Force" ] } provisioner "powershell" { use_pwsh = false script = "scripts/990_Run-BISF.ps1" } }

### Operating system and Environment details Build Server: Windows Server 2019 on-prem. Azure DevOps Agent, Citrix DaaS SDK. Only purpose of the VM is to be triggered be DevOps. OS to build: Azure Windows 11 23H2 Multi User with Citrix LTSR VDA 2507 ### Log Fragments and crash.log files The Packer process always breaks after 3+ hours, during the last Windows Update Restart run. There have been Windows Updates already at the beginning and many restarts in between.

2025-09-24T03:20:00+02:00: ==> azure-arm.win11-23h2-avd: Provisioning with powershell script: scripts/Datev-Sicherheitspaket-compact.ps1 -24T03:20:38+02:00: ==> azure-arm.win11-23h2-avd: ##[group]Installation DATEV Sicherheitspaket compact 7.89 2025-09-24T03:21:48+02:00: ==> azure-arm.win11-23h2-avd: Restarting Machine 2025-09-24T03:21:53+02:00: ==> azure-arm.win11-23h2-avd: Waiting for machine to restart... 2025-09-24T03:23:56+02:00: ==> azure-arm.win11-23h2-avd: pkrvmkno7ptxfxp restarted. 2025-09-24T03:24:00+02:00: ==> azure-arm.win11-23h2-avd: Machine successfully restarted, moving on 2025-09-24T03:24:03+02:00: ==> azure-arm.win11-23h2-avd: Pausing 1m0s before the next provisioner... 2025-09-24T03:25:07+02:00: ==> azure-arm.win11-23h2-avd: Uploading the Windows update elevated script... 2025-09-24T03:25:19+02:00: ==> azure-arm.win11-23h2-avd: Uploading the Windows update check for reboot required elevated script... 2025-09-24T03:25:31+02:00: ==> azure-arm.win11-23h2-avd: Uploading the Windows update script... 2025-09-24T03:25:45+02:00: ==> azure-arm.win11-23h2-avd: Running Windows update... 2025-09-24T03:25:59+02:00: ==> azure-arm.win11-23h2-avd: Searching for Windows updates... 2025-09-24T03:26:09+02:00: ==> azure-arm.win11-23h2-avd: Found Windows update (2012-04-05; 9,8 MB): Sicherheitsupdate fr Microsoft Visual C++ 2010 Service Pack 1 Redistributable Package (KB2565063) 2025-09-24T03:26:10+02:00: ==> azure-arm.win11-23h2-avd: Found Windows update (2024-11-12; 63,34 MB): 2024-11 .NET 6.0.36 Update for x64 Client (KB5047486) 2025-09-24T03:26:12+02:00: ==> azure-arm.win11-23h2-avd: Found Windows update (2025-05-22; 18,16 MB): Update fr Windows Security platform - KB5007651 (Version 10.0.27840.1000) 2025-09-24T03:26:14+02:00: ==> azure-arm.win11-23h2-avd: Found Windows update (2025-09-09; 107,06 MB): 2025-09 .NET 8.0.20 Update for x64 Client (KB5066233) 2025-09-24T03:26:15+02:00: ==> azure-arm.win11-23h2-avd: Downloading Windows updates (4 updates; 198,36 MB)... 2025-09-24T03:26:39+02:00: ==> azure-arm.win11-23h2-avd: Installing Windows updates... 2025-09-24T03:26:55+02:00: ==> azure-arm.win11-23h2-avd: Waiting for operation to complete (system performance: 0% cpu; 6% memory)... 2025-09-24T03:27:16+02:00: ==> azure-arm.win11-23h2-avd: Restarting Machine 2025-09-24T03:27:23+02:00: ==> azure-arm.win11-23h2-avd: Waiting for machine to restart... 2025-09-24T03:49:31+02:00: ==> azure-arm.win11-23h2-avd: Provisioning step had errors: Running the cleanup provisioner, if present... 2025-09-24T03:49:33+02:00: ==> azure-arm.win11-23h2-avd: ==> azure-arm.win11-23h2-avd: Deleting Virtual Machine deployment and its attached resources... 2025-09-24T03:50:54+02:00: ==> azure-arm.win11-23h2-avd: Deleted -> Microsoft.Compute/virtualMachines : 'pkrvmkno7ptxfxp' 2025-09-24T03:51:16+02:00: ==> azure-arm.win11-23h2-avd: Deleted -> Microsoft.Network/networkInterfaces : 'pkrnikno7ptxfxp' 2025-09-24T03:51:36+02:00: ==> azure-arm.win11-23h2-avd: Deleted -> Microsoft.Compute/disks : '/subscriptions//resourceGroups/rg-pur-packer-build/providers/Microsoft.Compute/disks/pkroskno7ptxfxp' 2025-09-24T03:51:36+02:00: ==> azure-arm.win11-23h2-avd: Removing the created Deployment object: 'pkrdpkno7ptxfxp' 2025-09-24T03:51:53+02:00: ==> azure-arm.win11-23h2-avd: ==> azure-arm.win11-23h2-avd: Deleting KeyVault created during build 2025-09-24T03:52:04+02:00: ==> azure-arm.win11-23h2-avd: Deleted -> Microsoft.KeyVault/vaults : 'pkrkvkno7ptxfxp' 2025-09-24T03:52:05+02:00: ==> azure-arm.win11-23h2-avd: Removing the created Deployment object: 'kvpkrdpkno7ptxfxp' 2025-09-24T03:52:24+02:00: ==> azure-arm.win11-23h2-avd: ==> azure-arm.win11-23h2-avd: The resource group was not created by Packer, not deleting ... 2025-09-24T03:52:25+02:00: Build 'azure-arm.win11-23h2-avd' errored after 3 hours 45 minutes: unexpected EOF ==> Wait completed after 3 hours 45 minutes ==> Some builds didn't complete successfully and had errors: --> azure-arm.win11-23h2-avd: unexpected EOF ==> Builds finished but no artifacts were created. ##[error]Error: The process 'C:\az-build-agent\_work\_tool\packer\1.14.2\x64\packer.exe' failed with exit code 1 Finishing: Packer build

### Screenshot ### EDIT1 I "solved" the issue today, by increasing vCPU from 2 to 6. The machine was still at 100% during the whole build, but it finished without issues this time. I checked all the deployment logs, and the last successfull build was on Packer v1.14.1 and the fails started with Packer v1.14.2. It is striking that Packer spawns super many Processes, like 10+, and they eat up all the cores. And the Packer Windows Update Plugin also eats 2 cores and still eats them after all updates are done. This feels wrong.