Compare two folders on Windows

1. Open both folders

Start Diffoniq and press Ctrl+O. Enter the left and the right folder, or use the Dir… buttons to browse. You can also drag two folders from File Explorer onto the Diffoniq window, or start Diffoniq with both paths:

"C:\Program Files\Diffoniq\Diffoniq.exe" "D:\project" "E:\project-copy"

That is the installer’s path; the portable version runs from the folder you unpacked it to. A folder on a network share works the same way: give the network path directly, such as \\server\share\project.

2. Read the list

Diffoniq lists both folders next to each other, one row for each file or folder pair. Where only one side has a file, the other side of the row stays empty. Click a column title to sort by it; a second click reverses the order. Every file that is not identical falls into one of four cases:

A row where only the name or the folder differs is a renamed or moved file, shown as one pair (see below). The status bar sums it all up: identical, different, left only, right only.

3. Decide what counts as a difference

Out of the box, Diffoniq ignores the modification date and time of files. A pair whose size differs counts as different without being read. Pairs of equal size are read in the background and compared by a content checksum while you browse; progress bars in the rows show that work, and the status bar counts what is still open. That answers the usual question, whether two trees are the same regardless of when the files were written, for example after a copy tool that did not keep the timestamps. The first run reads the files; a repeat run is answered from the hash cache.

If the date should count, open Options → Directory Comparison… and switch off Ignore Date and Ignore Time: files whose dates differ are then reported as different at once, without being read. That is quicker, but a file that was merely touched, copied or restored looks changed.

The same dialog holds the other choices: Ignore Case for folders that come from different worlds, such as an archive packed on Linux, where ReadMe.txt and readme.txt should count as the same file; Ignore Size, Ignore Single Files and Ignore Subdirectories; Look In Subfolders with Max Subfolder Level to limit the depth; and Detect Renamed Files.

4. Leave out what does not matter

Each side has an Exclude field. Enter wildcard patterns separated by semicolons, for example *.bak;tmp. An excluded folder disappears with everything inside it. The … button next to the field opens a list with one pattern per line. Comparing two working trees of a repository? Tick Hide what the .gitignore files of both folders ignore, and node_modules and build stay out on both sides.

Save a selection you use often: type a name in the Name field, press Save, and double-click it later to load the paths and filters and start the comparison in one step.

5. Look inside a changed file

Double-click a row, or press Return on it. Text files open side by side with the changed lines marked and the changed characters highlighted inside them. Tab jumps to the next difference, Backspace to the previous one, F7 hides the identical passages in between, and the overview bar beside the scroll bar shows where the differences are. Esc takes you back to the list.

Other file types open in a way that fits them: pictures side by side, programs by their version information, and any other file byte by byte, with the position of the first difference.

6. Bring the files in line

In a text file you can drag marked lines from one side onto the other and press Ctrl+S to save. Nothing is written before that, and Ctrl+Z takes a step back. To copy whole files or mirror a folder, see Folder Synchronization in the help.

7. Moved and renamed files

A file that was renamed or moved to another folder would normally show up as one missing file and one extra file. Diffoniq pairs them and shows them on one row, with the changed part of the name highlighted. The contents are still compared, so a file that only moved shows as identical. You can switch this off under Options → Directory Comparison… → Detect Renamed Files.

8. Keep the result

File → Export Report… writes what is on screen into one file: a single HTML page, plain text or JSON. A folder report lists the changes and only counts the identical files, so what you read is the list of differences. Send it, attach it to a ticket, or keep it as proof. The same report runs without a window, from a batch file or a scheduled task:

"C:\Program Files\Diffoniq\DiffoniqC.exe" /report "D:\project" "E:\project-copy" --out changes.html --content

The extension of the output file picks the format; --content compares files of equal size by content instead of leaving them unverified. The exit code tells a script whether anything differed. Details: Comparison Reports.

Good to know

• Comparing changes nothing in your folders. Files are only written when you save a merged text file or run a synchronization.
• Repeat checks use the hash cache. Diffoniq remembers the checksums it has computed, so a repeat comparison does not read unchanged files again. The price: a file that changed while its size and date stayed the same is not seen by a repeat check. Press Ctrl+F5 (Re-verify Contents) to read everything again.
• Esc stops the content check at any time, for example on a slow network share; what it had not reached stays unverified.
• A folder Diffoniq cannot read, for example because access is denied, stops the comparison with a message that names the folder. Grant read access or exclude the folder, then refresh.
• Archives are folders here. A ZIP or 7z file can take the place of either folder; see Compare two ZIP files. For a backup on a NAS or USB drive, see Check a backup against the original folder.

Other ways to compare folders

If you only need a list of names, Windows can do that without extra software: robocopy with the /L switch lists what it would copy and copies nothing, for example robocopy "D:\project" "E:\project-copy" /L /E. Free tools such as WinMerge and FreeFileSync also compare folders; our comparison page shows how they differ from Diffoniq, with the date we checked. If you come from Beyond Compare, see Diffoniq compared with Beyond Compare.

Questions

Can Diffoniq compare folders by content instead of by date? Yes, and that is how it is delivered: Ignore Date and Ignore Time are on, so files of the same size are compared by a content checksum. Switch both off under Options → Directory Comparison… if the date should count.

Does it include subfolders? Yes, with Look In Subfolders on. Max Subfolder Level sets how deep it goes.

Does it find renamed files? Yes. Renamed and moved files are paired and shown on one row.

Can I compare a folder with a ZIP file or a backup on a NAS? Yes. A folder, a ZIP file and other archives can be on either side, and a network path works. See the guides on comparing ZIP files and on checking a backup.

Can I run the comparison from a script? Yes. DiffoniqC.exe /report writes a report instead of opening a window and passes an exit code to your script.

Which Windows versions does it run on? Windows 10 and 11, 64-bit.

Try it on your own two folders

Diffoniq runs on Windows 10 and 11, 64-bit. Every feature is available for 30 days before you decide.

Windows is a trademark of Microsoft Corporation. WinMerge, FreeFileSync and Beyond Compare are trademarks of their respective owners. Diffoniq is not affiliated with any of them.