Error: spawn terraform ENOENT during Azure Pipeline Terraform

Question

When attempting to run terraform init as a task in an Azure Pipeline, it errors stating

spawn C:\hostedtoolcache\windows\terraform\0.12.7\x64\terraform.exe ENOENT

The installation appears fine, as basic functionality is verified during the install step (terraform version)

Relevant Pipeline Tasks

...
  - task: TerraformInstaller@0
    displayName: 'Install Terraform 0.12.7'
    inputs:
      terraformVersion: 0.12.7
  - task: TerraformTaskV1@0
    displayName: 'Terraform : init'
    inputs:
        command: 'init'
        workingDirectory: '$(System.DefaultWorkingDirectory)/Terraform/terraform'
...

Install Terraform 0.12.7

...
Verifying Terraform installation...
C:\hostedtoolcache\windows\terraform\0.12.7\x64\terraform.exe version
Terraform v0.12.7

Your version of Terraform is out of date! The latest version
is 0.12.19. You can update by downloading from www.terraform.io/downloads.html
Finishing: Install Terraform 0.12.7

Terraform : init

...
C:\hostedtoolcache\windows\terraform\0.12.7\x64\terraform.exe validate
##[error]Error: There was an error when attempting to execute the process 'C:\hostedtoolcache\windows\terraform\0.12.7\x64\terraform.exe'. This may indicate the process failed to start. Error: spawn C:\hostedtoolcache\windows\terraform\0.12.7\x64\terraform.exe ENOENT
Finishing: Terraform : validate

---

Many other users reported success fixing this by adding a checkout step, but the pipeline automatically does this (presumably previous versions did not), and manually adding it had no effect (actually took 2s longer due to different options).

Answer 1

Turns out the working directory path was incorrect, as the directory structure had been changed.

Changing all the named working directories from Terraform/terraform to just terraform corrected the issue.

Presumably both in this and cases where checkout was not performed, Terraform simply cannot locate main.tf, but the error is missing or lost.