Question: I am working on a .NET Core application for AWS. After reading [this post](https://stackoverflow.com/a/43243290/1987258), I added a file named `credentials` (without extension) in the folder: `C:\Users\Daan\`. In this text file, the access key and the secret access key are both there.

Unfortunately, the `Credentials` property is not set after running my code. Other properties, such as `Region` and `Profile`, are set correctly based on my `appsettings` file.

What becomes clear is that my program modifies the credentials file by adding this to the credentials file:

```none
toolkit_artifact_guid=[A GUID]

```

Can someone explain to me what this means, and how I fix it? By fixing, I mean that my credentials file is not modified but just read to set the `Credentials` property of my `awsOptions` variable.

It is important to know that I created this file myself (not with the CLI), I double checked that the credentials are correct, and that this is my code. Moreover, I do have .NET experience, but I just started working with AWS.

```
public void ConfigureServices(IServiceCollection services)
{
    services.AddMvc();
    var awsOptions = Configuration.GetAWSOptions();        
    services.AddDefaultAWSOptions(awsOptions);
    services.AddAWSService<Amazon.S3.IAmazonS3>();
}

```

Answer: 
"toolkit\_artifact\_guid" could get populated in the "credentials" file due to 3rd party extensions and updates. 

Most probably could be due to AWS Toolkit for Visual Studio.
According to [this link](https://docs.aws.amazon.com/toolkit-for-visual-studio/latest/user-guide/credentials.html), the documentation says:

> 
> The Toolkit for Visual Studio supports multiple sets of credentials
>  from any number of accounts. Each set is referred to as a profile.
>  When you add a profile to the Toolkit for Visual Studio, the
>  credentials can be stored using two mechanisms:
> 
> 
> Encrypted and stored in the SDK Credential Store.
> 
> 
> This store is also used by the AWS SDK for .NET and the AWS Tools for
>  Windows PowerShell. The SDK Credential Store is specific to your
>  Windows user account on your machine and can't be decrypted or used
>  elsewhere.
> 
> 
> The plain-text shared AWS credentials file used by other AWS SDKs and
>  the AWS CLI.
> 
> 
> To use the Toolkit for Visual Studio, at least one credential profile
>  must be available from either the SDK Credential Store or the shared
>  AWS credentials file.
> 
> 
> 

The location of the SDK Credential Store is `C:\Users\<your-windows-logon>\AppData\Local\AWSToolkit`. In that folder you will see a couple of JSON files: MiscSettings.json and RegisteredAccounts.json. In the MiscSettings.json file, there's a parameter called "LastAcountSelectedKey" which has a guid. Example:

```
{
    "MiscSettings" : {
        "AnalyticsCognitoIdentityId" : "<string redacted>",
        "AnalyticsMostRecentlyUsedCognitoIdentityPoolId" : "<string redacted>",
        "AnalyticsAnonymousCustomerId"                   : "<string redacted>",
        "lastselectedregion"                             : "us-east-1",
        "AnalyticsPermitted"                             : "true",
        "HostedFilesLocation"                            : "file://C:\\Users\\<your-windows-logon>\\.aws",
        "LastAcountSelectedKey"                          : "<GUID-we-see>"
    }
}

```

This GUID-we-see is what appears in the credentials file:

```
[default]
aws_access_key_id = ""
aws_secret_access_key = ""
region = us-east-1
toolkit_artifact_guid = GUID-we-see

```