Rufus lets you quickly and easily reformat an ESXi USB flash drive back to full capacity
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The executable is digitally signed and the signature should state:
"Akeo Consulting" (v1.3.0 or later)
"Pete Batard - Open Source Developer" (v1.2.0 or earlier)
Rufus: Reliable USB Formatting Utility (with Source), read the introduction, FAQ, and support forum.
If you're trying to re-purpose a flash drive that already had ESXi installed on it, you'll likely notice that even after attempts at reformatting it, it still has a tiny capacity.
This article will demonstrate a fix, step-by-step, showing that you can recover that flash drive very quickly and easily, with no command line stuff required. See also Rufus takes under a minute to create a bootable USB flash drive for ESXi installation TinkerTry.com Sep 10 2013
Over the years, having had to deal with this formatting issue in my home lab quite often, and I'm quite glad to finally have a quick and simple fix.
The advantages to using Rufus:
- free
- simple GUI
- can be run from an EXE that doesn't require any installation
- doesn't require careful attention to command line partitioning commands that can be a bit dangerous
- much faster than other methods, takes under a minute to follow my instructions below
- seems to work, every time, back on Windows XP, right through Windows 8
Here's the 4 minute video demonstrating the actual 3 second method of getting your flash drive back to full capacity, using Rufus.
, then follow the step-by-step instructions below.









For reference, here's other ways to regain your ESXi USB flash drive's full capacity.
HDDGuru HDD Wipe Tool
Reformatting an ESXi USB Stick by Ryan Birk, which highlights the use of HDDGuru HDD Wipe Tool.
Some drawbacks though, including:
- requires a full installation
- takes a long time to format (many minutes), with no quick option.

HP USB Disk Storage Format Tool
This oldie but goodie didn't require an installation to run, and had a quick format option that recovered the full size of the flash drive. It's getting hard to find a safe place to download anything these days, this EXE included, explained here:
hp-usb-disk-storage-format-tool.software.informer.com
Windows DISKPART
How To Reformat a Bootable ESXi USB Flash Drive by Brian Graf (VMware), Jun 03 2013
Works quite well, for those comfortable at the command line. No 3rd party software needed at all!
All Comments on This Article (3)
Sounds interesting (for some other projects), sure wish I had tools like this 4 years ago, when I got fed up fiddling with BartPE and the like, thank you for the heads-up.
Also, giving ESXi 5.5 is now an option:
http://TinkerTry.com/download-vsphere-5-lab
and more good news, you don't have to wipe any drives, you (may be able to) install to the USB flash drive you booted from, such as the Sandisk I pictured below. Then you have yourself a test ESXi 5.5 system, with no destruction of any drives required. Perhaps on some other system you care less about, to build confidence. Makes things a lot less scary (and back up first anyway).
Pretty nifty, eh? Let us know how it goes, if you're inclined to try, or I'll give it a shot in the coming weeks, once I get some other priorities behind me...
Rufus is great for creating a single-boot UFD, but for a multiboot UFD try my Easy2Boot Mutliboot project. I just tested this with the ESXi 5.1 ISO (just copy the ISO file to \_ISO\MAINMENU) and it booted fine - however I did not test that it would actually install to my system as I didn't want to wipe my internal HDD.
Easy2Boot works with pretty much any linux bootable ISO (just copy the ISO - no utility to run) and also works with Windows Install ISOs and other ISOs. You can even run multiple linux ISOs each with persistence if you add a special .mnu file for each ISO.
Chris
You can simply use diskpart to repurpose ESXi USB sticks.
http://www.sevenforums.com/tutorials/52129-disk-clean-clean-all-diskpart-command.html