Terraform · troubleshooting
Terraform found a module block it has not downloaded or linked yet, or one whose source changed since terraform init last ran. Run terraform init again in that directory.
Reproduced on Terraform 1.14.0, . Where the text says “reproduced”, the behaviour was run on that version, not taken from documentation.
First published
New to this? Read what is actually happening first, then come back to the steps.
terraform init
Look for - NAME in SOURCE for every module block
Lists each module as it installs it, with its source.
A few questions to narrow the list. Every answer ends in a command that confirms or rules the cause out — this cannot see your cluster, so nothing here is a certainty until you have checked.
Narrow it down
0 answered · nothing is sent anywhere
Cause space
2 of 2 still possible
Nothing ruled out yet. Answer the question above and the branches your answer eliminates will strike through here.
In this order. The first command usually contains the whole answer.
Step 1
terraform init
Lists each module as it installs it, with its source.
Look for - NAME in SOURCE for every module block
Ordered by how often each one turns out to be the answer.
A fresh clone, a CI job, or a different working directory, where .terraform does not exist.
Confirm
ls .terraform/modules/modules.json
No such file
Fix
terraform init -backend=false -input=false terraform validate
Reproduced on Terraform 1.14.0: installed the module and validated.
init installed the old set of modules; the configuration now asks for a different one.
Confirm
git diff -- '*.tf' | grep -n source
A changed or new source line
Fix
Skip this if you are mid-incident — the working part of the page is above. Worth reading afterwards, because understanding the mechanism is what stops the next one.
terraform init fetches every module the configuration uses into the .terraform directory. Adding a module, changing its source, or running in a fresh CI checkout without that directory leaves Terraform with nothing to read, and it says so. Re-running init fixes it.
Reproduced on 23 October 2026 with Terraform 1.14.0 and a local module. terraform validate before init printed Error: Module not installed and This module is not yet installed. Run "terraform init" to install all modules required by this configuration.
After the module's source was changed, the message became Error: Module source has changed, again asking for terraform init. In both cases nothing else was wrong with the configuration.
terraform init fixed both, and so did terraform init -backend=false, which suits CI jobs that only validate and have no state credentials.
| Where | What you see |
|---|---|
| terraform validate or plan | Error: Module not installed … This module is not yet installed. Run "terraform init" |
| After editing a module block | Error: Module source has changed … The source address was changed since this module was installed. |
Behaviour described here is drawn from official documentation. Where a figure could not be confirmed on an official page it is attributed in the text rather than stated as canonical.
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