| --- |
| page_title: 'State: Locking' |
| description: >- |
| Terraform stores state which caches the known state of the world the last time |
| Terraform ran. |
| --- |
| |
| # State Locking |
| |
| If supported by your [backend](/terraform/language/settings/backends/configuration), Terraform will lock your |
| state for all operations that could write state. This prevents |
| others from acquiring the lock and potentially corrupting your state. |
| |
| State locking happens automatically on all operations that could write |
| state. You won't see any message that it is happening. If state locking fails, |
| Terraform will not continue. You can disable state locking for most commands |
| with the `-lock` flag but it is not recommended. |
| |
| If acquiring the lock is taking longer than expected, Terraform will output |
| a status message. If Terraform doesn't output a message, state locking is |
| still occurring if your backend supports it. |
| |
| Not all backends support locking. The |
| [documentation for each backend](/terraform/language/settings/backends/configuration) |
| includes details on whether it supports locking or not. |
| |
| ## Force Unlock |
| |
| Terraform has a [force-unlock command](/terraform/cli/commands/force-unlock) |
| to manually unlock the state if unlocking failed. |
| |
| **Be very careful with this command.** If you unlock the state when someone |
| else is holding the lock it could cause multiple writers. Force unlock should |
| only be used to unlock your own lock in the situation where automatic |
| unlocking failed. |
| |
| To protect you, the `force-unlock` command requires a unique lock ID. Terraform |
| will output this lock ID if unlocking fails. This lock ID acts as a |
| [nonce](https://en.wikipedia.org/wiki/Cryptographic_nonce), ensuring |
| that locks and unlocks target the correct lock. |
