Sync: the same file everywhere, right now
Sync tools such as OneDrive, Dropbox, Google Drive and iCloud make a folder look the same on every device signed in to the account. Edit a spreadsheet on your desktop and the change appears on your laptop and phone within seconds. That is brilliant for working anywhere and sharing with colleagues.
The catch is that sync faithfully copies mistakes too. Delete a folder by accident and the deletion spreads. Overwrite a quote with the wrong figures and the bad version replaces the good one everywhere. If ransomware encrypts files on one laptop, the encrypted versions upload and replace the clean ones. Sync is about convenience and collaboration; it was never designed to protect history.
Backup: a separate copy you can rewind
A backup is an independent copy taken on a schedule and kept for a set period, so you can restore a file, a mailbox or a whole system as it was at an earlier point. The key words are independent and history. A proper backup lives in a different system with different credentials, and it keeps many versions, not just the latest.
Good backup software also records what changed between runs, so it only stores the differences after the first full copy. That makes it practical to keep daily versions for weeks and monthly versions for years without the storage bill growing out of control. The other feature to look for is separation. Backup storage should not be browsable as a normal network drive from staff computers, because anything a user can open, malware running as that user can also encrypt or delete.
Archive: data you must keep but rarely open
An archive is a long-term home for information you no longer work on but need to keep: closed client files, old financial years, former employees' mailboxes, completed project drawings. Moving it out of the live system keeps your everyday storage tidy, speeds up searches and can lower costs, because archive storage is priced for being read rarely.
Archives are not a substitute for backup either. If the archive is the only copy of a closed file, it needs its own protection. Many businesses treat the archive as a separate data set that is backed up less often, because it changes so little. A sensible pattern is to back up the archive once a month and after any large addition, such as closing off a financial year. Keep the archive read-only for most staff, so finished files cannot be edited or deleted by accident.
Where people get caught out
The classic mistake is a business that keeps everything in Dropbox and believes it is backed up. Version history helps for a while, but there are time limits, and restoring hundreds of files one at a time after a ransomware event is painful. Another is moving old files to an 'archive' USB drive in a drawer, which quietly becomes the only copy and then fails to spin up when needed.
A third is using a backup as an archive by never deleting anything, then finding the retention settings removed the oldest copies years ago. Each tool has its own rules about how long it keeps things, so check them rather than assuming. Microsoft 365 retention policies, backup retention and archive storage tiers can all automatically remove data after a set time. Those defaults were chosen by a vendor for a typical customer, not for your contracts or your accountant's advice.
What a small office typically needs
For most offices of five to fifty people the sensible mix looks like this: sync for daily work through OneDrive, SharePoint or Google Drive; a separate cloud backup of that whole environment, plus any server or NAS; and a simple archive area, often a read-only SharePoint site or a dedicated storage account, for finished work you must keep for legal or client reasons. Firms with large media files, such as architects or video producers, may also want a cheaper archive storage tier for finished projects, which can noticeably reduce what they pay for live storage.
Write down which tool does which job, who can delete from each, and how long each keeps data. That one page answers most of the questions an insurer, auditor or new IT provider will ask, and it stops anyone assuming that one tool covers the others. Review it whenever you add a new system, such as a practice management app or a new shared mailbox, because new data stores are exactly what tends to fall outside existing protection.
In short
- Sync copies changes instantly, including deletions and encrypted files.
- Backup is independent and keeps history so you can rewind.
- Archive keeps rarely used data long term and still needs protecting.
- Write down which tool does which job and how long each keeps data.