hashicorp/terraform · error

encountered a malformed backend state file that contains sta

Error message

encountered a malformed backend state file that contains state for both a 'backend' and a 'state_store' block

What it means

A single backend state file must describe EITHER a 'backend' block OR a 'state_store' block, never both (the two fields are mutually exclusive storage mechanisms). Seeing both at backend_state.go:110 means the file is internally inconsistent or corrupt.

Source

Thrown at internal/command/workdir/backend_state.go:111

		return nil, fmt.Errorf("unsupported backend state version %d; you may need to use Terraform CLI v%s to work in this directory", versionSniff.Version, versionSniff.TFVersion)
	}

	// If we get here then we can be sure that this file at least _thinks_
	// it's format version 3.
	var stateFile BackendStateFile
	err = json.Unmarshal(src, &stateFile)
	if err != nil {
		return nil, fmt.Errorf("invalid syntax: %w", err)
	}
	if stateFile.Backend == nil && stateFile.Remote != nil {
		// It's very unlikely to get here, but one way it could happen is
		// if this working directory was most recently used with Terraform v0.8
		// or earlier, which didn't yet include the concept of backends.
		// This error message assumes that's the case.
		return nil, fmt.Errorf("this working directory uses legacy remote state and so must first be upgraded using Terraform v0.9")
	}
	if stateFile.Backend != nil && stateFile.StateStore != nil {
		return nil, fmt.Errorf("encountered a malformed backend state file that contains state for both a 'backend' and a 'state_store' block")
	}
	if stateFile.StateStore != nil && stateFile.StateStore.ProviderSupplyMode == "" {
		// Check for this, as lacking this data can cause problems later when an empty provider version
		// is encountered. This error will make debugging much easier.
		return nil, fmt.Errorf("encountered a malformed backend state file with a 'state_store' block that is missing the required 'provider_supply_mode' property")
	}

	return &stateFile, nil
}

func EncodeBackendStateFile(f *BackendStateFile) ([]byte, error) {
	f.Version = 3 // we only support version 3
	f.TFVersion = version.SemVer.String()

	switch {
	case f.Backend != nil && f.StateStore != nil:
		return nil, fmt.Errorf("attempted to encode a malformed backend state file; it contains state for both a 'backend' and a 'state_store' block. This is a bug in Terraform and should be reported.")
	case f.Backend == nil && f.StateStore == nil:

View on GitHub (pinned to c9def3e214)

Solutions

1. Open .terraform/terraform.tfstate, determine which storage mechanism is actually in use, and delete the other top-level block.
2. Safest: remove .terraform/ and re-run 'terraform init' with the single correct configuration.
3. Check source-control history of the file to understand how both blocks came to be written.

Example fix

// before — .terraform/terraform.tfstate contains both:
{ "version":3, "backend":{...}, "state_store":{...} }
Error: encountered a malformed backend state file that contains state for both a 'backend' and a 'state_store' block

// after — keep only the one your config uses:
{ "version":3, "state_store":{...} }
// or simply:
$ rm -rf .terraform && terraform init

// Reject a file that declares both storage mechanisms before calling ParseBackendStateFile.
func hasBothBackendAndStateStore(src []byte) bool {
    var probe struct {
        Backend    *json.RawMessage `json:"backend"`
        StateStore *json.RawMessage `json:"state_store"`
    }
    _ = json.Unmarshal(src, &probe)
    return probe.Backend != nil && probe.StateStore != nil
}

null

null

When it happens

Trigger: ParseBackendStateFile finds Backend != nil && StateStore != nil after a successful decode.

Common situations: Manual editing or git-merging of .terraform/terraform.tfstate spliced two configs together; a botched migration between the classic backend mechanism and the newer state_store mechanism; files copied between directories.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• unsupported backend state version %d; you may need to use Te
• this working directory uses legacy remote state and so must
• error loading state: %w
• failed to write state: %w
• blob metadata %q was empty

AI-assisted analysis of hashicorp/terraform@c9def3e214 (2026-08-07). Data as JSON: /api/errors/c47cc32d7f2a5239. Report an issue: GitHub.