All tools

Extension repair

Fix incorrect file extensions

Extension fixing helps when files cannot be opened because the suffix no longer matches the actual file type. It is especially useful for downloaded archives and renamed compressed files.

Best for

Use this when archives or downloaded files have wrong suffixes and need their real extension restored.

Rename examples

Fix ZIP suffix

important.zip111

important.zip

Fix RAR suffix

backup.rar001

backup.rar

Restore archive type

archive.7z.tmp

archive.7z

Common use cases

  • Repair archive extensions after downloads or transfers.
  • Identify disguised archives by reading file signatures.
  • Batch fix files before extraction or handoff.

How to use it

  1. 1Add files with suspicious extensions.
  2. 2Choose the extension fix rule and keep archive-only mode when appropriate.
  3. 3Preview detected extensions before applying.

FAQ

Does this change file contents?

No. The rule reads file headers to infer type, then changes the file name extension only.

Why is archive-only mode recommended?

Archive signatures are usually clearer than many other file types, so archive repair is the safer default.

Related tools

All tools

Apply this rule locally

Renamio runs on Windows and macOS, previews every rename, and keeps rename history for safer batches.

Download Renamio