# Restore Your System from a Backup

If your system runs into data loss or a failure, a backup file lets you return it to a known-good state. This page walks through restoring a backup and explains what to check before you begin.

## Before you begin

- Confirm you already have a backup that includes your system configuration and any files you rely on, such as custom voice prompts and CDR (Call Detail Record) logs, the records that show each call's time, numbers, and duration.
- Review the version rules for restoring a backup:
  - A backup taken from an **earlier** software version can be restored onto a **later** version. For example, a backup made on v84.5.0.55 restores cleanly onto v84.5.0.57.
  - A backup taken from a **newer** software version cannot be restored onto an **older** version. For example, a backup made on v84.5.0.57 will not restore onto v84.5.0.55. Check the version the system is running before you start, because the restore has no way to downgrade the software.

:::tip
Before you restore, take a fresh backup of the current system and note the software version it is running. If the restore does not give the result you expected, you then have a clean point to return to.
:::

## Restore a backup

1. Sign in to the web portal and open **Maintenance > Backup and Restore**.
2. Find the backup file you want to apply, then click the restore icon ![Restore](/images/pbx/Restore.png) in its row.
3. Confirm the action by clicking **OK** in the dialog that appears.
4. Reboot the system so the restored data takes effect.

:::caution
Rebooting takes the phone system offline for a few minutes. Any calls in progress are dropped, and no calls (including 911 and other emergency calls) can be placed or received until the system finishes starting up. Schedule the restore and reboot for a maintenance window whenever you can.
:::

## Result

After the reboot, the system runs on the data from the backup file.

:::danger
Restoring a backup overwrites the current configuration completely: every setting on the system is replaced by the contents of the backup file. This cannot be undone, so double-check that you selected the correct backup before you confirm.
:::