attempted to encode a malformed backend state file…

Error message

attempted to encode a malformed backend state file; state_store configuration data is missing

What it means

StateStoreConfigState.Validate() found ConfigRaw == nil. ConfigRaw is the msgpack/json-encoded state_store configuration body; without it Terraform cannot reconstruct the state_store's arguments at plan/apply time, so encoding is refused.

Solutions

Re-run `terraform init` to regenerate the file with ConfigRaw populated.
Delete the corrupt file and re-init from the state_store configuration block.
Restore from backup.

Example fix

rm .terraform/terraform.tfstate
terraform init

Defensive patterns

Strategy: validation

Validate before calling

// pre-flight: require ConfigRaw for state_store
if s.ConfigRaw == nil {
    return errors.New("state_store requires configuration data; populate ConfigRaw before encoding")
}

Type guard

func (s *StateStoreConfigState) hasConfigRaw() bool { return s != nil && s.ConfigRaw != nil }

Prevention

Encode the config body when constructing StateStoreConfigState in code.
Let `terraform init` own the file.

When it happens

Trigger: A state_store record missing its `config` field — partial file write, hand-editing, or programmatic construction that omitted ConfigRaw.

Common situations: Interrupted `terraform init`, third-party tool that builds StateStoreConfigState without encoding the config body, file corruption.

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

AI-assisted analysis of hashicorp/terraform@d32a084675 (2026-08-11). Data as JSON: /api/errors/98fa0e449e6b628c. Report an issue: GitHub.

Appendix: source

Thrown at internal/command/workdir/statestore_config_state.go:55

	return s == nil || s.Type == ""
}

// Validate returns true if there are no missing expected values, and
// important values have been validated, e.g. FQNs. When the config is
// invalid an error will be returned.
func (s *StateStoreConfigState) Validate() error {
	// Are any bits of data totally missing?
	if s.Empty() {
		return fmt.Errorf("attempted to encode a malformed backend state file; data is empty")
	}
	if s.Type == "" {
		return fmt.Errorf("attempted to encode a malformed backend state file; state store type is missing")
	}
	if s.Provider == nil {
		return fmt.Errorf("attempted to encode a malformed backend state file; provider data is missing")
	}
	if s.ConfigRaw == nil {
		return fmt.Errorf("attempted to encode a malformed backend state file; state_store configuration data is missing")
	}

	// Validity of data that is there
	err := s.Provider.Source.Validate()
	if err != nil {
		return fmt.Errorf("state store is not valid: %w", err)
	}

	// Version information is required if the provider isn't builtin or unmanaged by Terraform
	switch s.ProviderSupplyMode {
	case getproviders.BuiltIn, getproviders.Reattached, getproviders.DevOverride:
		// These modes do not require version information
	case getproviders.ManagedByTerraform:
		if s.Provider.Version == nil {
			return fmt.Errorf("state store is not valid: provider version data is missing despite provider %s being managed by Terraform.", s.Provider.Source.ForDisplay())
		}
	default:
		panic(fmt.Sprintf("State store provider %q (%s) has unknown supply mode %q. This is a bug in Terraform and should be reported.", s.Provider.Source.Type, s.Provider.Source.ForDisplay(), s.ProviderSupplyMode))

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