How to Merge Two Folders on Windows 10 Safely

To merge two folders on Windows 10, the safest approach is to copy one folder into the location that already contains the other. Windows combines the folder structure instead of deleting the destination folder. Files that exist only in one folder are added, while files with the same name in the same subfolder are handled as conflicts so you can choose what to keep.

This is different from replacing a folder. A merge keeps destination-only files unless you deliberately delete or overwrite them.

How folder merging works in Windows 10

Microsoft documents copying, cutting, and pasting folders as standard File Explorer operations. When two folder trees overlap, File Explorer can combine their contents. What happens next depends on the files inside them:

• A file exists only in the source: it is copied into the destination.
• A subfolder has the same name: Windows combines the contents of those matching subfolders.
• A file has the same name and extension in the same location: Windows presents a conflict choice so you can replace, skip, or review the files.
• Two files contain the same data but have different names: Windows treats them as separate files and keeps both.

Merge two folders with File Explorer

Use copying rather than cutting for the first pass. That leaves the original source folder intact until you confirm that the merged destination contains everything you need.

1. Locate both folders. If the folders already have the same name, leave them as they are. If they have different names, you can either rename the source to match the destination or open the source and copy its contents into the destination folder instead.
2. Select the source folder and copy it. Press Ctrl+C, or right-click the folder and choose Copy.

3. Open the destination's parent folder. For example, if the existing destination is D:\Backup\Project, open D:\Backup.
4. Paste the source folder. Press Ctrl+V or right-click an empty area and choose Paste. Windows will combine the matching folder trees rather than remove destination-only files.

5. Resolve any duplicate file names. If Windows finds files with the same name in the same relative folder, review the prompt before continuing.

What to choose when Windows finds duplicate files

The conflict dialog is the step where data can actually be overwritten. Choose carefully:

• Replace the files in the destination uses the incoming source versions for the conflicting names.
• Skip these files keeps the versions already in the destination and does not copy the conflicting source files.
• Let me decide for each file is the safest option when the two folders contain different versions that you need to compare individually.

After the copy finishes, open a few important subfolders and confirm that the expected files are present. Only then should you delete the old source folder if you no longer need it.

Merge folders with Robocopy for large folder trees

For a large collection of nested folders, Windows 10 also includes Robocopy. Microsoft's Robocopy documentation confirms that the command applies to Windows 10 and that the /E option copies all subdirectories, including empty ones.

For example:

robocopy "C:\Work\Project" "D:\Backup\Project" /E

This copies the source tree into the destination tree while leaving destination-only files in place. If you want to preview what Robocopy would do first, add /L; Microsoft documents that option as listing planned actions without copying, deleting, or timestamping files.

Avoid /MIR for a normal merge. Microsoft defines /MIR as /E plus /PURGE, which can delete files and directories that exist only in the destination. That behavior is useful for an exact mirror but is the opposite of a non-destructive merge.

If you actually want to replace the destination folder

Replacing a folder means making the destination contain only the source version. File Explorer's normal same-name copy behavior is not designed to remove destination-only files. If that is truly your goal, back up anything important, delete or rename the old destination folder, and then copy the source folder into its place. For scripted work, Robocopy /MIR can create an exact mirror, but use it only after a preview because it removes destination-only items.

One Windows 10 support note

These File Explorer and Robocopy steps still apply to Windows 10, but Microsoft states that standard support for Windows 10 ended on October 14, 2025. See the Windows 10 end-of-support notice if you are deciding whether to keep using the operating system.