⁦F.⁩ Checking the backup

Checking that the backup is intact

Why

A drive can fail silently: the backup looks complete until you need to recover something from it. The check reads the backup files from the drive and compares each one with the checksum recorded during the backup. It writes nothing.

Before you start

  • It is best to check after disconnecting and reconnecting the backup drive. The program then really reads the data from the drive, not from the computer's memory.
  • The check reads all files in the backup's table of contents, so for a large backup it takes a long time, even several hours. You can interrupt it with the “Stop” button.
  • An encrypted backup: have the backup password ready.

Step by step

  1. In the menu on the left, click “Restore”.
  2. In the “Where we restore from” box, click “Choose…” and choose the main backup folder, not a dated folder.
  3. If the backup is encrypted, enter the password in the “Password” box.
  4. Click “Check backup”.

What you should see

Below the buttons you see the progress. At the end the “Backup check” window appears with the summary “Done:”, that is, the number of files checked, their size and the time taken.

The check covers all files in the backup's table of contents, that is, the newest saved state of each file. It does not read older states of files that have changed. Versions with a Sigelith seal are checked by the content audit (see “Checking that nobody has tampered with files in the backup”).

What next

  • Check the backup every now and then, for example once a month, and always before you throw away or format the original files.
  • The check tells you that the files in the backup are intact. Whether they can be restored is shown by a trial restore (see “Trial restore”).

If something goes wrong

  • The “Backup check” ends with errors: the window lists the files with a problem, for example “the file is missing from the backup” or “the contents differ from the checksum recorded during the backup”. See “A check reports changed or damaged files”.
  • A note about files without a checksum: some files went into the backup without a checksum, for example when an interrupted backup was finished. If the file at the source has not changed, the program compares the backup with it and adds the checksum to the table of contents. Otherwise it checks only the size.
  • “This folder has no backup table of contents”: the wrong folder was chosen. Choose the main backup folder, the one chosen as the save location when the backup was created.
  • “Check backup” is inactive: choose the backup folder. For an encrypted backup, also enter the password.