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The pre-clone checklist

Fifteen minutes of preparation that prevents the most common cloning disasters.

Last updated August 2026

Nearly every cloning horror story starts with a step in this list being skipped. Working through it takes about a quarter of an hour and removes most of the ways the process can go badly wrong.

Before you touch any software

Back up what you cannot replace

Cloning erases the destination drive irreversibly, and the classic mistake is selecting the drives the wrong way round. Copy your documents, photos and anything else irreplaceable to a location that is neither the source nor the destination — an external drive or cloud storage. This is the only item on the list that is genuinely non-negotiable.

Check the health of the source drive

Read its SMART data with CrystalDiskInfo or a similar tool. Reallocated sector counts, pending sectors or a status other than Good mean the drive is deteriorating. That does not stop you cloning, but it changes the approach: work quickly, avoid unnecessary reboots, and use ddrescue or another tool that copes with read errors instead of aborting on the first one.

Measure used space, not drive size

Compare the used space on the source with the capacity of the destination. If used space exceeds about 70% of the new drive, clear some out first — see cloning to a smaller SSD.

Note the manufacturer's marketing gigabytes

A drive sold as 500 GB shows up in Windows as roughly 465 GiB, because the industry counts in powers of ten and Windows displays powers of two. Always plan with the smaller number.

Windows housekeeping

Handle BitLocker

Search for “Manage BitLocker” in the Start menu and check whether encryption is on. Modern Windows 11 machines often have device encryption enabled by default. Suspend or fully decrypt it before cloning, and make sure your recovery key is saved somewhere off the machine either way.

Run a filesystem check

Open an administrator command prompt and run chkdsk C: /f. It will schedule itself for the next restart. Cloning a filesystem with existing errors reproduces the errors faithfully on the new drive.

Clean up

Empty the Recycle Bin, run Disk Cleanup including the “Clean up system files” option, uninstall software you no longer use, and delete any Windows.old folder. Less data means a faster clone and a tidier result.

Defragment, but only mechanical drives

If the source is a spinning hard drive, run Optimise Drives. It speeds up the clone and makes any partition shrinking possible. Never defragment an SSD — Windows runs TRIM on those instead, which is what the same dialog does automatically when it detects one.

Write down your licences and passwords

Cloning normally preserves everything, but if you end up doing a clean install instead you will want your Windows product key, your application licences, and access to your password manager. Five minutes now saves an unpleasant evening later.

Hardware preparation

Make sure both drives can be connected simultaneously

Desktops usually have spare SATA ports or M.2 slots. Single-bay laptops need a USB-to-SATA adapter or an NVMe enclosure. Confirm you actually have the right adapter for the drive's form factor before you start — SATA, M.2 SATA and M.2 NVMe are not interchangeable.

Confirm the machine supports the new drive

NVMe boot support is not universal on systems older than around 2016. Check whether a BIOS update is available. Check too whether your motherboard disables SATA ports when an M.2 slot is used, which is common and surprises people.

Identify each drive unambiguously

Note the model number, serial and capacity of both drives, from Disk Management or the drive label. Cloning software will ask you to choose between physical disks, and “Disk 0” and “Disk 1” are not enough information to be confident with.

Keep the laptop plugged in

A clone interrupted by a flat battery leaves a half-written destination drive. Disable sleep and hibernation for the duration.

Software preparation

Pick the tool before the evening you need it

Check that its free edition will actually clone a system disk — several will not. Our comparison table has that in a column.

Create rescue media in advance

If your tool builds a bootable USB, make it now, while Windows still runs. Rescue media is worthless if you can only create it on a machine that already boots.

Download from the vendor, not a download portal

Third-party download sites are a persistent source of bundled adware in this software category. Go to the developer's own domain.

The last check before you press start Read the confirmation screen out loud. It names the drive that is about to be erased. If that name is not the new, empty drive, stop.

The list, condensed

  1. Separate backup of irreplaceable data — done.
  2. SMART health of the source drive — checked.
  3. Used space fits the new drive with headroom — confirmed.
  4. BitLocker suspended or decrypted, recovery key saved.
  5. chkdsk run clean.
  6. Junk deleted, mechanical source defragmented.
  7. Both drives connected and individually identified.
  8. Rescue media created.
  9. Machine on mains power, sleep disabled.
  10. Destination drive confirmed on the final screen.

Questions

Do I really need a backup if I am only cloning?

Yes. The destination is erased without warning, and selecting the wrong drive takes one misread line. A backup makes that mistake annoying rather than permanent.

Should I defragment before cloning?

Only a mechanical hard drive. It speeds the clone and allows the partition to be shrunk if needed. Do not defragment an SSD.

What if the source drive is already failing?

Move fast and use a tool designed for damaged media. ddrescue skips unreadable areas, logs them, and retries later rather than aborting. Avoid repeated reboots and long scans, which put extra load on a dying drive.

How do I tell which physical disk is which?

Disk Management shows model and capacity per disk; the drive label carries the serial. Match those, not drive letters. If both drives are identical, connect only one at a time while you identify it.