How to fix Error: error running apply in Terraform

First, run terraform plan to generate an execution plan without modifying infrastructure. This helps identify configuration errors before apply:

terraform plan -out=tfplan

Review the output carefully. If terraform plan fails, the issue is likely in your configuration or provider setup. If terraform plan succeeds but apply fails, the problem occurs during resource creation.

A locked state file prevents apply operations. Check if the state is locked:

terraform force-unlock <LOCK_ID>

If you see state lock errors, you can attempt to unlock it. First, verify no other Terraform process is running. If using remote state (S3, Terraform Cloud), check the backend configuration and ensure only one process accesses it at a time.

Apply failures often stem from authentication issues. Verify credentials are set correctly for your cloud provider:

For AWS:

export AWS_ACCESS_KEY_ID=your_access_key
export AWS_SECRET_ACCESS_KEY=your_secret_key
export AWS_REGION=us-east-1

For Azure:

az login

For GCP:

gcloud auth application-default login

Ensure credentials have permissions to create/modify resources in your plan.

Enable Terraform debug logging to see detailed error messages:

export TF_LOG=DEBUG
terraform apply -auto-approve

This generates verbose output showing exactly where the apply failed. Review the logs for provider-specific error messages that reveal the root cause (quota limits, permission errors, API failures, etc.).

Ensure your Terraform configuration is syntactically correct and all references are valid:

terraform validate
terraform fmt -check

The validate command checks for syntax errors and missing required arguments. The fmt command identifies formatting issues. Fix any reported errors before attempting apply again.

Ensure your provider version is compatible with your configuration. Lock provider versions in production:

terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5.0"
    }
  }
}

Run terraform init after updating provider requirements to download the correct version.

Check if the state file is corrupted or out of sync:

terraform state list
terraform state show <resource_name>

If state shows resources that no longer exist in infrastructure, use terraform refresh or terraform import to sync state with actual infrastructure. Out-of-sync state often causes apply failures.