Packer doesn't seem to upload files to Windows

I’m trying to learn Packer for Windows after using it with Linux for about a year. I don’t know Windows well; but I can’t seem to upload files with Packer to my Windows instance. The file says it uploads, but when I start the instance; the file is not there. What am I doing wrong?

poc.json:

{
    "variables": {
        "environment": "redacted",
        "contact": "redacted",
        "service": "redacted"
    },
    "builders": [
        {
            "profile": "nonprod",
            "region": "us-west-2",
            "type": "amazon-ebs",
            "subnet_id": "redacted",
            "security_group_id": "redacted",
            "source_ami": "redacted",
            "instance_type": "t2.micro",
            "communicator": "winrm",
            "winrm_username": "Administrator",
            "ami_name": "{{user `service`}}-v7.0-{{user `environment`}}-Packer-{{timestamp}}",
            "tags": {
                "Name": "{{user `service`}}-v7.0-{{user `environment`}}-Packer-{{timestamp}}",
                "Service": "{{user `service`}}",
                "Environment": "{{user `environment`}}",
                "Contact": "{{user `contact`}}",
                "Packer": "true"
            },
            "run_tags": {
                "Name": "{{user `service`}} Packer Builder",
                "Service": "{{user `service`}}",
                "Environment": "{{user `environment`}}",
                "Contact": "{{user `contact`}}",
                "Packer": "true"
            },
            "launch_block_device_mappings": [
                {
                    "device_name": "xvdb",
                    "volume_size": 500,
                    "volume_type": "gp2",
                    "delete_on_termination": true
                }
            ]
        }
    ],
    "provisioners": [
        {
            "type": "powershell",
            "inline": [
                "C:/ProgramData/Amazon/EC2-Windows/Launch/Scripts/InitializeInstance.ps1 -Schedule",
                "C:/ProgramData/Amazon/EC2-Windows/Launch/Scripts/SysprepInstance.ps1 -NoShutdown",
                "Get-Disk | where partitionstyle -eq \"raw\" | Initialize-Disk -PartitionStyle GPT -PassThru | New-Partition -AssignDriveLetter -UseMaximumSize | Format-Volume -FileSystem NTFS -NewFileSystemLabel \"Data Drive\" -Confirm:$false",
                "mkdir C:/Packer/",
                "mkdir C:/Packer/Misc_Installers/"
            ]
        },
        {
            "type": "file",
            "source": "./files/startup.ps1",
            "destination": "C:\\Packer\\"

        }
    ]
}

PACKER_LOG=1 packer build poc.json:

2020/05/20 08:04:05 [INFO] (telemetry) Starting provisioner file
==> amazon-ebs: Uploading ./files/startup.ps1 => C:\Packer\
2020/05/20 08:04:05 packer-builder-amazon-ebs plugin: Uploading file to 'C:\Packer\startup.ps1'
2020/05/20 08:04:05 packer-provisioner-file plugin: [INFO] 1515 bytes written for 'uploadData'
2020/05/20 08:04:05 [INFO] 1515 bytes written for 'uploadData'
startup.ps1 1.48 KiB / 1.48 KiB [=====================================================================================================] 100.00%
startup.ps1 1.48 KiB / 1.48 KiB [=====================================================================================================] 100.00%
2020/05/20 08:04:08 packer-builder-amazon-ebs plugin: <Objs Version="1.1.0.1" xmlns="http://schemas.microsoft.com/powershell/2004/04"><Obj S="progress" RefId="0"><TN RefId="0"><T>System.Management.Automation.PSCustomObject</T><T>System.Object</T></TN><MS><I64 N="SourceId">1</I64><PR N="Record"><AV>Preparing modules for first use.</AV><AI>0</AI><Nil /><PI>-1</PI><PC>-1</PC><T>Completed</T><SR>-1</SR><SD> </SD></PR></MS></Obj></Objs>#< CLIXML
2020/05/20 08:04:08 packer-provisioner-file plugin: closing
2020/05/20 08:04:08 closing
2020/05/20 08:04:08 packer-builder-amazon-ebs plugin: <Objs Version="1.1.0.1" xmlns="http://schemas.microsoft.com/powershell/2004/04"><Obj S="progress" RefId="0"><TN RefId="0"><T>System.Management.Automation.PSCustomObject</T><T>System.Object</T></TN><MS><I64 N="SourceId">1</I64><PR N="Record"><AV>Preparing modules for first use.</AV><AI>0</AI><Nil /><PI>-1</PI><PC>-1</PC><T>Completed</T><SR>-1</SR><SD> </SD></PR></MS></Obj><startup.ps1 1.48 KiB / 1.48 KiB [==================================================================================================] 100.00% 2s
2020/05/20 08:04:08 [INFO] (telemetry) ending file

Just an update on this. The reason I am unable to upload files is because it’s blocked by corporate ‘hardened’ Windows.

I got around the problem by uploading my (6GB) files to S3 and downloading them to the Builder. The pros is that it is MUCH faster than using WinRM.

Hey @wblakecannon , thank you for including how you got around this issue. Were you able to use Packer to retrieve your S3 file and upload it into the windows server that it is building? I am trying to configure it so that the file is already on the machine upon start up.