Check Backup: How to Test That a Restore Works (Overview)

How Do You Check Backup Health Properly?

Backup checks and how often to run them

Check	How often	Time needed
Last successful backup date	Monthly	2 minutes
Selected folders still correct	Every 3 months	5 minutes
Restore 3 to 5 random files	Every 3 months	15 minutes
Restore an older version	Every 6 months	10 minutes
Full restore drill on a spare drive	Once a year	A few hours

In ten years of backup work, I have seen many backups that looked fine and restored nothing useful. Folders were excluded, keys were lost, or the app had stopped months earlier. A short, regular test catches all three.

What Do You Need Before You Start?

You need access to the backup app, your encryption key or password, and a spare folder or drive for restored files. Never restore a test over your original files.

• The login for your backup service and any private key
• A test folder, such as “Restore-test,” on your desktop or an external drive
• A short list of files to test: a photo, a document and a large file

How to Check Backup Status and Run a Test Restore

These steps work for most cloud backup services, as well as Time Machine and File History.

1. Open the backup app. Note the date and time of the last successful backup.
2. Review the selection. Confirm your key folders and external drives are still included.
3. Pick three to five files. Choose different types and folders, including one you changed recently.
4. Restore to the test folder. Select “restore to a different location” if the app offers it.
5. Open every file. Check that photos display, documents open and videos play.
6. Restore an old version. Choose a file and restore it from a date at least a month ago.
7. Compare sizes. Check that restored files match the original file sizes.
8. Write down the result. Note the date, files tested and any problems.

How to Verify Specific Backup Types

Cloud computer backup

Sign in on the provider’s website, not just the app, and browse your files. Restore a few through the web as well. That proves you can recover even if your computer is gone.

Time Machine on Mac

Open the folder in Finder, enter Time Machine, step back to an older date and restore a file. Check the date of the latest backup in System Settings.

File History on Windows

Right-click a file, choose to restore previous versions, and pick an older one. Then restore it to a different folder and open it.

iPhone and Android

Check the last backup time in settings. For iPhone, Apple shows the date and time under Back Up Now in iCloud Backup. A full phone test needs a reset, so most people only do it when moving to a new phone.

Common Backup Errors and How to Fix Them

Frequent problems found during a backup test

Problem	Likely cause	Fix
Last backup weeks ago	Changed password, sleep settings or full disk	Sign in again, free space, run a manual backup
Folder missing from backup	Folder moved or renamed	Add the new path to the selection
External drive data gone	Drive left unplugged too long	Reconnect and check the provider’s drive rules
Files are placeholders only	Online-only cloud files	Set key folders to keep files on the device
Cannot decrypt the restore	Lost private key	Recover the key from your password manager

The “online-only” problem is common with OneDrive, Dropbox and Google Drive. Read backup and sync to see why sync folders need special care.

How Often Should You Test a Backup?

Test quarterly at minimum, and after any big change, such as a new computer or a new backup service. Business data deserves monthly tests. Our guide to backup timing explains how to match schedules to risk.

This habit is also what CISA recommends. Its ransomware guide advises people to “regularly test the availability and integrity of backups” (CISA). The test is part of the backup, not an extra.

Privacy During a Test Restore

Restored files are new copies, so delete the test folder when you finish. If you restore to a shared or work computer, wipe the files afterward. Keep your private key out of plain text notes.

For the bigger picture of how backups fit together, see our pillar guide on how to back up to the cloud.

Frequently Asked Questions

Is a green status icon enough to trust a backup?

No. A green icon means the app ran without errors it could detect. It does not prove that the right folders are selected or that the files open. Only a test restore, followed by opening the files, shows that you can actually get your data back.

Should I test-restore over my original files?

Never. Always restore to a separate test folder or drive. Restoring over originals can replace newer files with older ones, and if the backup is damaged, you could lose good data. After the test, compare the files, then delete the test copies.

How do I test a full computer restore safely?

Use a spare drive or an old computer, not your main machine. Restore the full backup there, then check folders, file counts and a sample of files. Once a year is enough for most homes. It also shows how long a real disaster restore would take.

What should I log after each backup test?

Note the date, the backup tool, which files you restored, whether they opened, and how long it took. Add any errors and how you fixed them. A simple spreadsheet works. Over time, the log shows whether your backups stay reliable.

Can backup software verify backups automatically?

Many tools run integrity checks that confirm stored data matches its checksums. These checks are useful, but they test the stored data, not your ability to find and open files. Keep automatic verification on, and still do a manual test restore each quarter.