What to Back Up Before Moving a Windows Computer to Linux

Copying your Documents folder is not enough preparation for erasing Windows.

A good migration backup answers three questions:

1. Where is the data really stored?
2. What credentials or recovery information will you need later?
3. Can you prove the backup opens from somewhere other than the computer you are about to change?

Back up the obvious folders

Start with the normal user data:

• Desktop;
• Documents;
• Pictures;
• Videos;
• Music;
• Downloads if it contains anything important.

Also search for project folders and personal files stored outside those standard locations.

A folder on C:\ or another internal drive does not become safe just because it sits outside your profile directory.

Check OneDrive for online-only files

OneDrive Files On-Demand can show files in File Explorer that are not actually stored locally.

Microsoft identifies online-only items with the cloud status icon.

Those files require internet access to download.

Before changing the disk, verify that important cloud data is accessible through the account and, if you are creating an offline external backup, make sure the files are actually downloaded before copying them.

Synchronization is useful, but it is not the same thing as proving you have an independent backup.

Preserve browser and account access

Think beyond bookmarks.

You may need:

• bookmarks/favorites;
• saved passwords;
• authenticator access;
• recovery codes;
• browser profiles;
• important extensions or extension settings;
• account email addresses.

If passwords are stored only in one local browser profile, losing that profile can create a much larger migration problem than losing the bookmarks.

Use the browser's supported sync or export methods where appropriate and verify you can sign back in.

Check locally stored email and application data

Some applications keep important information locally.

Examples can include:

• mail archives;
• accounting or database files;
• custom templates;
• application presets;
• local note databases;
• game saves;
• fonts;
• license files.

Do not assume that because an application has an account login, all of its data lives in the cloud.

Save encryption and recovery information

Disk and firmware changes can trigger recovery prompts.

Before changing partitions or encryption, preserve relevant recovery keys somewhere outside the computer.

For Windows systems using BitLocker or Device Encryption, make sure the recovery information is actually available.

Do not store the only copy of a disk-recovery key on the disk it unlocks.

Developers have extra hidden dependencies

A development machine may also contain:

• SSH keys;
• GPG keys;
• Git configuration;
• local environment files;
• signing credentials;
• container volumes;
• local databases;
• unpushed Git commits;
• scripts outside repositories.

Be especially careful with secrets.

They may need secure backup, but they should not be dumped into a normal public Git repository.

Make an independent copy

Useful backup destinations can include:

• an external drive;
• another computer or NAS;
• a cloud backup;
• more than one of those for important data.

Windows File History can maintain copies on an external drive or network location, but do not assume that a configured backup job proves the current migration data is complete.

Test the backup before erasing Windows

Open files from the backup destination.

Check several categories:

• a document;
• photos;
• a large file;
• any important archive or database;
• exported browser data;
• recovery-key records.

If the backup is encrypted, make sure you know how to unlock it.

A migration backup is complete when the data is both copied and recoverable.

Only then should you move on to partitioning or a full-disk Linux install.

For the installation-strategy decision, see Dual Boot or Full Linux Migration? Choosing the Safer Path.