How to fix Error: Error creating Transfer Server: ResourceExistsException in Terraform

List all Transfer Servers in your AWS region to see if it already exists:

aws transfer list-servers --region us-east-1

Look for a server with the same endpoint or hostname that matches your Terraform configuration. You can also check the AWS Console by going to AWS Transfer Family > Servers.

If the server exists, note its Server ID (format: s-1234567890abcdef0). This is what you'll need to import into Terraform.

Review what Terraform thinks currently exists in your state file:

terraform state list | grep aws_transfer_server

If nothing appears, Terraform's state is empty for Transfer Servers. This indicates a state mismatch.

To refresh your state with actual AWS resources:

terraform refresh

This updates your local state to match what actually exists in AWS. If the server appears after refresh, re-run:

terraform plan

The plan should show zero changes if everything is now in sync.

If the server exists in AWS but not in your Terraform state, import it:

terraform import aws_transfer_server.example s-1234567890abcdef0

Replace s-1234567890abcdef0 with your actual server ID from step 1.

After import, Terraform will fetch all the server's attributes from AWS and add them to your state file. Your resource block should match the imported configuration:

resource "aws_transfer_server" "example" {
  identity_provider_type = "API_GATEWAY"
  # ... other attributes will be populated
}

Verify the import succeeded:

terraform state show aws_transfer_server.example

To prevent state mismatch issues, use a remote backend instead of local state. AWS S3 + DynamoDB is recommended:

terraform {
  backend "s3" {
    bucket         = "my-terraform-state"
    key            = "transfer-server/terraform.tfstate"
    region         = "us-east-1"
    dynamodb_table = "terraform-locks"
    encrypt        = true
  }
}

Initialize the backend:

terraform init

Alternatively, use Terraform Cloud:

terraform {
  cloud {
    organization = "my-org"
    workspaces {
      name = "transfer-servers"
    }
  }
}

A remote backend ensures your state is shared across team members and CI/CD systems, preventing duplicate resource creation.

If you have duplicate resource definitions in your Terraform code, remove the duplicate:

Instead of:

resource "aws_transfer_server" "main" {
  identity_provider_type = "API_GATEWAY"
  domain                 = "SFTP"
}

resource "aws_transfer_server" "main" {
  # Accidentally duplicated
  identity_provider_type = "API_GATEWAY"
  domain                 = "SFTP"
}

Keep only one resource block. Then run:

terraform plan

The plan should show no changes. If it tries to destroy and recreate, don't apply—instead, import the existing resource as shown in step 3.

Once you've imported the resource or fixed the state mismatch, validate your configuration:

terraform validate
terraform plan

The plan should show no changes if everything is correctly synced. If it still wants to apply changes, review them carefully—they may represent intentional infrastructure updates.

terraform apply

If applying succeeds with zero changes, your issue is resolved. The Transfer Server is now properly tracked in Terraform state.