Starting agent on windows fails with 'Starting config-downloader'

[ineednewpajamas]

Describe the bug
Starting the agent on version 1.4.37916 via userdata, or a tool like Chef, results in:

config-downloader.exe : 2025/10/15 15:04:18 Starting config-downloader, this will map back to a call to
amazon-cloudwatch-agent
At C:\Program Files\Amazon\AmazonCloudWatchAgent\amazon-cloudwatch-agent-ctl.ps1:304 char:9
+         & $CWAProgramFiles\config-downloader.exe --output-dir "${JSON ...
+         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (2025/10/15 15:0...loudwatch-agent:String) [], RemoteException
    + FullyQualifiedErrorId : NativeCommandError

Steps to reproduce
& "C:\Program Files\Amazon\AmazonCloudWatchAgent\amazon-cloudwatch-agent-ctl.ps1" -a fetch-confi g -m ec2 -c file:"C:\ProgramData\Amazon\AmazonCloudWatchAgent\cloudwatch-agent.json" -s 1> c:\temp\1.txt 2> c:\temp\2.txt

What did you expect to see?
No error

What did you see instead?
The above error and failure to start the agent

What version did you use?
Version: 1.4.37916

What config did you use?
Config:

{
  "metrics": {
    "append_dimensions": {
      "InstanceId": "${aws:InstanceId}",
      "InstanceType": "${aws:InstanceType}"
    },
    "metrics_collected": {
      "Memory": {
        "measurement": [
          "Available MBytes",
          "% Committed Bytes In Use"
        ]
      }
    }
  }
}

Environment
OS: Windows

Additional context
Very similar to #871

[duncanjwatson]

I am experiencing the same issue today using chef. Builds that ran on 10-10 didn't experience this issue and the amazon-cloudwatch-agent hasn't been updated during the intervening period to my knowledge.

[KrisDTitian]

Also seeing this, when downloading/installing from S3 latest the version in the release notes is 'Amazon CloudWatch Agent 1.300060.0', but latest tag is 'v1.300059.0'.
Tested command on system with CWAgent/1.300059.0b1207 which worked as expected.
*as an update this download string worked for me:
https://s3.amazonaws.com/amazoncloudwatch-agent/windows/amd64/1.300059.0b1207/AmazonCloudWatchAgent.zip

[movence]

Thank you for bringing this issue to our attention.

I have tested the agent 1.300060.0 installation and startup on a Windows 2022 Base instance without encountering any problems. As I am unfamiliar with Chef, I would appreciate additional details regarding the steps to reproduce this issue.

[ineednewpajamas]

@movence there's a command in the description that reproduces it, chef not needed.

[duncanjwatson]

The suspicion is that this is similar to #871 where the issue shows up where both stdout and stderr are redirected as noted in the OPs issue

[ineednewpajamas]

This occurs if only stderr is redirected. stdout doesn't seem to make a difference.

[movence]

Thanks for clarifying this, @ineednewpajamas and @duncanjwatson. Yes, it looks the same as the linked issue where this recent change is causing the problem (#1454). I'm currently looking into a mitigation