USB thumb / flash drives and Microsoft Windows

A quick technical post!

Occasionally, I’m called upon to deal with minor issues for users of USB thumb drives, and I thought I’d pull together a few little tips and tricks here which help me get things sorted.

The first is the logical format of the drive.  Commonly, these drives come formatted as FAT32.  That’s great if you want to see all the disk if it’s larger than 4GB, it’s quite quick, and well supported across many platforms.  If you want to use files larger than 4GB (let’s say, a virtual hard disk for VMware Player or Microsoft Virtual PC) however, FAT32 won’t help.  Try copying a 12GB .vhd file onto an empty FAT32 formatted 32GB thumb drive, and you’ll get the dreaded “disk full” error :

Your options at this point are NTFS or exFAT.  They’re both nice formats, but they’re not supported in many operating systems, or by many other platforms such as consoles.  Windows XP will use exFAT with a hotfix, whilst Windows Vista (SP1) and above support it natively.  Mac OS X (10.6.5 and above) can support it, but that’s about it.  NTFS is read only by default in OS X too.

My personal preference in the two is NTFS, but formatting a large thumb drive to NTFS is not always a straightforward process.  Try to format the disk straight from Windows Explorer, and you’ll probably notice that NTFS is not an available choice :

To make the NTFS option available, we need to visit the Windows Device Manager (devmgmt.msc) to optimize the device for performance (this can be undone after format if you wish).  Note that after making this change, you must ALWAYS eject the drive in the operating system before removing it.  After opening Device Manager, find your drive under “Disk drives”, right click it and select “Properties” :

On the “Policies” tab, select “Optimize for performance” and click OK :

It’ll probably take a couple of minutes for this to complete, but when the above pictured dialogue box disappears, you can close Device Manager and attempt to format your drive again.  Note the addition of the NTFS option in the Windows Explorer format dialogue box :

Using Windows Explorer to format your drive is not the only way, and sometimes, if you’re experiencing problems, using the command prompt can be a little easier.  There are a couple of options here for a drive that is already formatted to FAT32.  The first is to use the “convert” command, to simply change the format from FAT32 to NTFS.  This can be used when you have data on the drive and should be non destructive.  Where your drive is using the letter “X”, you should use the command with the following syntax :

convert x: /fs:ntfs

To simply format the drive as NTFS, which will destroy any data on the drive, you should use the “format” command.  The syntax to format the “X” drive to NTFS is as follows :

format x: /fs:ntfs

Now you should have a drive which can support files larger than 4GB, and you can take your virtual machines with you wherever you go!  🙂

Unfortunately, these little drives can throw up other problems, such as retaining drive letters when not plugged in, and generally being a pain in the posterior.  Sometimes, the only fix for these issues is to uninstall them from Device Manager.  If the device isn’t around for you to plug in though, it won’t be visible in Device Manager, and the question I’m often asked is “so how do you get rid of it then?”.  The answer is a little obscure, but relatively simple.

Firstly, we need to open a command prompt.  This allows us to enter commands that will show us devices that are not present in the system, and open Device Manager with those settings.  The commands to enter, in order, are :

set devmgr_show_nonpresent_devices=1
cd %systemroot%\system32
start devmgmt.msc

This will open Device Manager with the required settings, but your disk will still not be visible.  From the “View” menu, you should first select “Show hidden devices”.  At this point, all the drives you’ve had attached in the past should pop up as shaded items under “Disk drives”, and you can right click any of them and select “Uninstall”.  When you’ve removed your device, close Device Manager and your Command Prompt, and you’re all set.  Note that this can apply to all devices you’ve had attached to your system but aren’t there anymore.  Uninstalling old devices can be therapeutic, and give you a slightly cleaner system!

Well, so much for a quick little post – that dragged on a bit!  Hopefully it’ll help one or two people out there get away from some of the niggles related to USB thumb / flash drives and other devices.

The Zoo Keeper



By TheZooKeeper

An Azure Cloud Architect with a background in messaging and infrastructure (Wintel). Bearded dog parent who likes chocolate, doughnuts and Frank's RedHot sauce, but has not yet attempted to try all three in combination!

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