Error: resource already exists means Terraform is trying to create a resource that already exists in your cloud provider but isn’t tracked in Terraform’s state file.

Why this happens

Terraform maintains a state file that maps your configuration to real infrastructure. When a resource exists in the cloud but not in state — because it was created manually, the state was lost, or another workspace created it — Terraform tries to create it fresh and the cloud provider rejects the duplicate.

What causes this error

1. Resource created manually — someone created it in the AWS/GCP console
2. State file lost or corrupted — Terraform doesn’t know about existing resources
3. Another Terraform workspace created it — different state files

Fix 1: Import the existing resource

terraform import aws_s3_bucket.my_bucket my-bucket-name
terraform import aws_instance.my_server i-1234567890abcdef0

After importing, run terraform plan to verify the config matches the actual resource.

Fix 2: Remove from state and recreate

# If you want Terraform to manage a fresh resource
terraform state rm aws_s3_bucket.my_bucket
# Then delete the actual resource manually, then run terraform apply

Fix 3: Use data sources instead

If you don’t want Terraform to manage the resource, reference it as a data source:

data "aws_s3_bucket" "existing" {
  bucket = "my-existing-bucket"
}

Alternative solutions

Use import blocks (Terraform 1.5+) for declarative imports without CLI commands:

import {
  to = aws_s3_bucket.my_bucket
  id = "my-bucket-name"
}

Prevention

• Never create resources manually that Terraform manages. Use terraform apply for all changes.
• Use remote state (S3 + DynamoDB) to prevent state conflicts across teams.

Related: Terraform cheat sheet · terraform init Failed · Terraform State Lock Error · Terraform vs Pulumi