Some things came back and others did not.
WHAT USUALLY HAPPENS
Files restored, database not, or the reverse A table missing from a truncated dump Media files excluded by a backup setting One site restored from a multi-site account, leaving others untouched
DIAGNOSING
Check what the archive actually contained. Extract it and look.
Check whether the database import completed, or stopped partway.
Check whether an exclusion setting in your backup tool left something out.
FIXING IT
Restore the missing part from the same backup if it is there Restore from a different backup if not
Reconstruct from another source: the payment gateway for orders, an archive service for content
WHAT PEOPLE DISCOVER
That uploads were excluded to keep archives small That the database was never included at all That one site on the account was never backed up
THE PREVENTION
Verify what your backups contain rather than assuming. Extract one and look at it.
Restore-test properly, checking that content and media are present rather than only that the site loads.
