Convert RAR to CAB

Programs such as Windows deployment tools, installers, and older Microsoft utilities may require a Cabinet file instead of a RAR archive. Converting it means extracting the RAR contents and building a new CAB archive; the original RAR compression is not transferred.

What the RAR format is

RAR is a proprietary archive format created by Eugene Roshal and commonly produced by WinRAR or the rar command-line utility. It supports compression, password-based encryption, recovery records, solid archives, and multi-volume sets such as archive.part1.rar. You commonly encounter RAR files in software downloads, backup sets, and shared collections of files.

WinRAR, 7-Zip, PeaZip, and compatible command-line tools can extract RAR archives. A password-protected RAR must be unlocked before its contents can be repackaged.

What the CAB format is

CAB, or Microsoft Cabinet, is an archive format designed for software distribution and Windows installation workflows. Microsoft installers, device-driver packages, Windows servicing tools, and deployment systems use CAB files to store one or more compressed files.

CAB supports compression methods such as MSZIP and LZX, can divide large archives across cabinet volumes, and integrates with Windows tools including expand.exe, makecab.exe, and DISM. It is preferable to ZIP or RAR when a particular Windows installer or deployment utility explicitly requires CAB.

How to actually convert RAR to CAB

Using WinRAR and MakeCab on Windows

1. Install WinRAR or 7-Zip. In WinRAR, open the RAR file and choose Extract To; in 7-Zip, choose 7-Zip → Extract to “archive\”.
2. Extract the contents into a working folder such as C:\Work\Extracted. Preserve the directory structure if the software expects relative paths.
3. Open Command Prompt and create a Cabinet directive file, for example C:\Work\cab.ddf, containing:
   .OPTION EXPLICIT
.Set CabinetNameTemplate=output.cab
.Set Cabinet=on
.Set Compress=on
.Set CabinetFileCountThreshold=0
.Set FolderFileCountThreshold=0
.Set FolderSizeThreshold=0
.Set DiskDirectoryTemplate=.
C:\Work\Extracted\file1.dll
C:\Work\Extracted\setup.exe
4. Replace the example file paths with every file to include. Add one path per line; use quoted paths if a path contains spaces.
5. Run makecab /F C:\Work\cab.ddf from Command Prompt. Windows writes output.cab to the directory specified by DiskDirectoryTemplate, usually the current directory.
6. Test the result with expand -D output.cab to list its contents, or extract it with expand output.cab -F:* C:\Work\Test.

makecab.exe is included with supported Windows installations and Windows SDK components. If it is not available, install the Windows SDK or use Microsoft Cabinet SDK tools such as cabarc.exe.

Using a graphical CAB creation utility

Extract the RAR with WinRAR, then use a CAB-capable utility such as CabPack or a Cabinet SDK front end to select the extracted files, choose MSZIP or LZX compression when offered, set the output filename, and create the cabinet. Verify that the utility creates a standard Microsoft CAB rather than merely renaming the extension.

Online services

Online archive converters such as CloudConvert or Convertio may support RAR extraction, but CAB output is not consistently available. Check the supported output formats before uploading; do not use an online service for confidential files, installer source, credentials, or encrypted archives.

Quality, compatibility, and limitations

This is a repackaging operation: files are decompressed from RAR and compressed again using CAB, so the result may have a different size and cannot preserve RAR-specific features such as recovery records, solid-block settings, or RAR volumes.

CAB is not a general replacement for RAR. Its file and cabinet size limits, compression method support, and multi-cabinet behavior depend on the consuming Windows tool. If an installer expects a specific internal filename, folder layout, compression method, or catalog signature, copying the files into a CAB will not recreate those installer metadata requirements; use the original vendor packaging process or the relevant Windows SDK instead.