Since I am using Windows, WinSCP is the next tool I tried.

First, start the host’s SSH service by

1. Select the host in vCenter and click Configure tab.
2. Then select Services from the left-side panel under the System section.
3. Start the SSH service there.

Now it’s ready to use WinSCP. Simply log in with the host’s root account and then navigate to the storage volume at /vmfs/volumes.

Windows Explorer

Supporting VMDK seems to be a feature built right into the Windows system. If you are using a system that runs Windows 7 or above, you may be able to map the image file right through Windows Explorer.

Navigate to the fold that hosts VMDK file in Windows Explorer, right-click the file and choose Map Virtual Disk.

Select the drive letter you want to map to, and click OK button on the Map Virtual Disk window.

To disconnect, right-click the mapped drive and choose Disconnect Virtual Disk.

It works beautifully when it works. When it’s not, it’s time to seek alternative options.

VMware Workstation

VMware Workstation is VMware’s desktop solution for virtualization. It has the “Map Virtual Disks” feature built in that opens VMDK in a wider format. If the method of using Windows Explorer doesn’t work out, VMware Workstation is next one in the line to try.

Go to File menu and select Map Virtual Disks… from the drop-down list to start the process.

vSphere Disk Development Kit

The  “VMware-mount” command line is the one you can use to mount a VMDK disk without a GUI interface. The tool is part of the vSphere Disk Development Kit, so you need to download and install the kit to use the tool.

To mount a VMDK file (saved at C:\temp) in read-only mode use the following command:

vmware-mount.exe X: “C:\Temp\TestVM.vmdk”

If the VMDK file contains more than one partition you can use the parameter /v:x to mount the other volumes:

vmware-mount.exe /v:2 X: “C:\Temp\TestVM.vmdk”

If you need a writeable access, just use the parameter “/m:w“. This is extremely helpful if you need to replace a broken system file.

vmware-mount.exe /m:w X: “C:\Temp\TestVM.vmdk”

If you want to list all the mounted virtual drives use /L:

vmware-mount.exe /L

The command line is easy to use and powerful, but I am finding it’s not so easy to get the Development Kit installed on my computer for some reason.

OSFMount

OSFMount is a 3rd party free image mounting tool that mounts not only ISO format images but also VMDK files in Windows with a drive letter. It works on pretty much all versions of Windows.

It’s fairly easy to use the tool. Click the Mount new… button at the bottom of the window and follow the instructions.

If you have other alternative options, feel free to share. It’s never enough to have a reliable tool that does the job well in hand.

/Update on July 8, 2020/

As some of the commenters pointed out, the open-source archiving tool 7-Zip does happen to be the easiest way to open the VMDK file for you. By all means, give 7-Zip a try first and if it failed, try something mentioned above.