VMDK file format

.vmdk · disk image · introduced 2003 by VMware

What is a VMDK file?

VMDK is VMware's virtual disk format and the most portable VM disk in the industry. Public cloud OVF templates and Vagrant boxes ship as VMDKs because every hypervisor reads them. The streamOptimized variant uses per-chunk zlib so VMDKs can be downloaded over HTTP and streamed straight into a hypervisor without intermediate decompression.

Most readers reach this page after double-clicking a .vmdk file and finding their operating system unsure what to do with it. The good news: VMDK is a well-understood format with mature tooling on every major platform. It is supported in one click by mainstream archivers on Windows, macOS, and Linux.

How to extract a VMDK file

Opening a .vmdk file is straightforward on every modern operating system. The exact steps depend on which platform you are on:

On Windows

Locate the .vmdk file in File Explorer.
Right-click the file. If you have 7-Zip installed, choose 7-Zip → Extract Here. On Windows 11 the built-in extractor handles ZIP, 7z, RAR and several other formats directly through Extract All…
If prompted, pick a destination folder and click Extract.
The extracted files appear in a folder next to the original archive.

On macOS

Find the .vmdk file in Finder.
Install The Unarchiver from the Mac App Store, or Keka for both creating and extracting.
Right-click the file → Open With → The Unarchiver (or just double-click after Unarchiver is set as the default).
The extracted folder appears next to the archive.

On Linux

Use your file manager: right-click the archive → Extract Here (file-roller on GNOME, Ark on KDE).

On the command line, run one of:

7z x archive.vmdk    # works for almost any format

The files appear in the current directory.

How to create a VMDK file

To pack files into a .vmdk archive, you typically need an archiver that supports writing this format. Not every tool can create every format — for example, only WinRAR can create real RAR files. The sidebar lists the software known to read and write VMDK.

On the command line, the canonical create command is:

# Use 7-Zip, PeaZip, or the format's reference tool to create .vmdk files.

If you regularly create archives at scale, a dedicated archive automation suite can wrap this command in scheduled jobs, integrity checks, and offsite replication.

Strengths

Universal hypervisor support
Streamable variant
Mature tooling

Weaknesses and limitations

Multiple subformats can confuse
Single descriptor + multiple data files in some modes

Typical use cases

VMware virtual machines
Vagrant base boxes
OVF appliance distribution

Technical details

VMDK uses the None / sparse / streamOptimized (zlib) algorithm and is identified on disk by the magic byte sequence 4B 44 4D. The standard MIME type is application/x-vmware-vmdk. The format is an open specification and is free for any use.

Frequently asked questions

Is VMDK safe to open?

Archive files are containers — they are only as safe as what they contain. A .vmdk from a trusted source is fine; one received from a stranger can hold malicious executables, scripts, or files engineered to exploit bugs in your archiver. Always keep your archiver updated, and never run unknown executables that come out of an archive. A safe workflow is to extract into a sandbox and scan the contents before opening anything.

What is the maximum file size?

Modern implementations support archives in the multi-terabyte range. The practical limit is your filesystem (FAT32 caps at 4 GB; ext4, NTFS, APFS, and exFAT all comfortably handle multi-TB files).

Can I password-protect a VMDK?

Some archivers can wrap VMDK files in an encrypted container, but the format itself does not always include built-in encryption. Check your archiver's documentation.

How does VMDK compare to other formats?

See our format comparison pages such as ZIP vs 7z, ZIP vs RAR, and tar.gz vs tar.xz for side-by-side feature tables.