Help center

Guides & troubleshooting

Step-by-step fixes drawn from the WinMerge manual FAQ and day-to-day compare workflows.

Folder select Line endings Large files Explorer order Archives External tool Antivirus Best practices

Browse dialog

Cannot select a folder in Browse

Browse into the folder you want to compare.
Do not select nested files or subfolders. Click Open when Folder Selection appears in the File name field.
If something is already selected, type a random string in File name and click Open. When that name is not found, WinMerge opens the folder.

Compare options

Every line looks different

Files may use different line ending styles (Windows vs Unix). By default WinMerge compares those endings.

Open Edit, Options.
Open the Compare page.
Enable Ignore carriage return differences.
Re-run the compare.

Large files

Folder says different, file compare says identical

WinMerge uses Quick Contents for large files during folder compare so huge trees stay efficient.

What to try

Raise the Quick Contents threshold for large files, then refresh the folder result.

Confirm

Double-click the pair to open a full file compare. Trust the file pane for final merge decisions.

Shell

Control left vs right from Explorer

When you compare multiple files from Windows Explorer, the file you right-click becomes the first (primary) item. Remaining items follow selection order. Right-click the file you want on the left side.

Open archives and OpenOffice files

Click Options (or Edit, Options).
Open Archive Support.
Enable Detect archive type from file signature.
Compare again. For Perry-style patch zips, select the same zip on both left and right.

CLI

WinMerge as an external diff tool

-e

Close with a single Esc press after you finish.

-x

Quit silently when files are identical.

/ub

Do not add temporary paths to the MRU lists.

If the host app cannot pass switches, wrap WinMerge in a batch file that calls it with /e /u and your %1 %2 %3 arguments.

Security

Antivirus warnings explained

Open-source Windows installers are occasionally quarantined by heuristic engines. That does not mean the project ships malware.

Verify SHA-256 against the published digest
Re-download only from the winmerge.io Download page
Use the per-user installer if elevation is blocked
Report false positives to your AV vendor with the hash

See download integrity notes

Tips

Best practices

Filter early

Use regex file filters to drop build outputs, caches, and vendor trees.

Save projects

Use Save project in the select dialog for repeated path pairs.

Diff-only view

Hide similar lines with View, Diff Context, 0 lines.

Codepages

If you see question marks, check Options, Codepages, and try disabling Detect codepage info.

Still stuck? Browse the full FAQ or feature details.