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Can I install programs on an external drive?


Windows XP-Home is installed on my C: drive. Will programs, games and so on run if installed on my external E: drive or do they have to be on the same drive as Windows?

The short answer is yes, but there are, as always a few caveats and clarifications I need to make.

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If when you set it up a program allows you to choose a destination drive to install onto, it shouldn’t matter if that drive is C:, your Windows drive, or some other hard drive internal or external. For the most part they’re all just drives, and the fact that the setup program gives you the option means there shouldn’t be an issue.

For the record, if the setup program doesn’t give you a choice then it may be an issue and I’d avoid trying to circumvent it.

Now, many external drives are removable. USB drives, for example, can be removed from your computer either while it’s not running, or after clicking a “safely remove hardware” for the device. In the later case, if a program on your removable drive is running, “safely remove” may fail. All files on the external drive must not be in use, and a program running from the drive is definitely “in use”. You’ll need to make sure that all programs installed on the external drive are shut down before attempting to remove the drive.

Now, that sounds simple enough but more complex packages often install software that runs automatically when you start your machine, either in the form of explicit start-up menu items, or as system services. You may not think you’re running any software that’s installed on that external drive, but in reality it may have installed something that is. You’ll need to figure out what that is, and take steps to disable it, or shut it down before you remove the drive.

“You’ll need to make sure that all programs installed on the external drive are shut down before attempting to remove the drive.”

Along those same lines, if the drive is not installed when you boot your system, you may get error messages on start up if a prior installation of software onto that drive also added startup items. Without the drive installed,those startup items may not be found, and errors may result. Menu items and shortcuts relating to the software installed on the external drive may also revert to Windows defaults until some time after the drive is reinstalled.

Finally, don’t expect application portability by installing it to an external drive. By that I mean that installing an application to an external drive, and then taking that drive to a different computer and expecting the application to work on that machine. This may work for simpler applications, but setting up a complex application is as much about setting up the Windows registry as it is about just placing files. The registry will have only been set up on the first machine. Theoretically it might be possible to set up the software on machine A, then set it up again on machine B if the drive letters are identical, but I’d expect that to be highly error prone. It’s also quite possibly against many applications licenses or terms of use since you’re technically installing it on two machines.

So there are a number of issues related to removable media, but if you’re just installing your software to a second hard drive, and it just happens to be an external drive, I wouldn’t expect that scenario to be an issue for you.

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16 comments on “Can I install programs on an external drive?”

  1. Excellent advice, Leo.

    Some aapplications have been designed to run external drives, such as the MS Word compatible processor, “ABIword Portable,” the Thunderbird Browser, and many Open Office applications.

    Carrying these portable applications on an external drive or jump drive can be helpful if you’re a student or you use various computers.

  2. There is a program call MojoPac that allows one to install software on a USB drive, iPod or portable hard drive because it vitualizes the Registry. You can run MS Office and other programs like Adobe Creative Suite, and move the drive from computer to computer and use the installed applications. Very cool . Find out more here:

  3. How to protect my data on my portable hard drive, from infections, while connecting to other people’s pc ?
    Thanks for any info.

    Hash: SHA1
    If your hard drive (or USB thumb drive) has a physical
    “read-only” switch to prevent writing to the device, use
    that. Unfortunately, not many do these days for some reason.
    – From a purely pragmatic point of view the answer is that you
    really can’t … at least not with 100% certainty. The best
    steps to take include:
    * ONLY connect to PCs you absolutely trust
    * turn off “auto play” on your own computer
    * virus scan the drive immediately on connecting it back to
    your own computer.

    Version: GnuPG v1.4.7 (MingW32)

  5. I am tired of formatting my hard drive and installing all the service pack files and bunch of application each time my computer hit by a virus.
    1) From the above comments it is clear that we can install Application on separate drive internal or external as long as the apps get installed on that separate drive.
    Is it possible to create partitions of my current internal hard drive C i.e. install operating system on C and install all the apps on the partition drive and if I have to format my C drive will the apps still work with that operating system when it gets reinstalled on C drive.
    2) How to make a complete copy of C drive that includes boot and license files and all the apps to put it on DVD or multiple DVD’s so in case of formatting hard drive I can just put the DVD and install everything.
    Any comments will be greatly appreciated.
    Installing on an external drive doesn’t somehow prevent viruses from attacking what’s installed out there – they’re just as vulnerable. Taking a full backup image once you’ve set up a clean machine is one way to have something you can restore to so as to avoid having to reinstall all the time.
    But if you’re constantly getting re-infected, that simply shouldn’t be, and I’d re-evaluate your security software and/or your safety habits.
    – Leo09-Jan-2009

  6. I currently have a desktop PC and laptop setup on my wireless network. I have recenly added an external hard drive, which I have also made available to both computers on the network.

    I am curious to know, if I install applications onto the external hard drive can both netwroked computers run that application?

    Thank you!

    Typically, no. Installation also sets up information on the machine you’re installing it on, most notably in the registry, which won’t be set up for those other machine. A few apps can work as you describe, but almost all that use a setup program do not.

    – Leo
  7. I have a problem. I use Steam for my games. (It is an internet system to download and file games. I plugged in my external hard drive to my computer, and the space on it jumped from 300gb to 14000gb. I installed a game, but when I tried to run it, it told me that it was missing maps. How can I fix this? It dosn’t give me a file location to put it or anything.

  8. I installed adobe master collection CS4 on a hard drive and then the hard drive broke and i got a new one and now i cant install adobe master collection CS4 again.

    Adobe’s copy protection scheme can be somewhat painful at times. You should be able to contact Adobe customer support for assistance, though.


  9. I am reformatting an older pc with the orignal windows xp. c drive it very little ram ( runs slower now with all the updates). I have an internal hardrive with 2 gig…can I install xp on here and pc will run? also, do I have to have all the service packs installed? Plus, I looked up all the drivers to update and there are 78. Not sure which ones I really need as they all say “optional” on them. (dell pc 4300)

    Thank you!

  10. Hi There Leo – Thanks for the help. Okay there is this product “USB 2.0 to IDE/SATA Cable with Power Adapter -here’s the link: –
    Question is can programs be run with this from external old xp hard drive connected with usb to new machine with new windows 7 professional? This could be so fantastic for so many if possible.

    It depends on the program. If the program would work under Windows 7 without needing to have its setup program run, then sure, it’ll run no matter what drive it’s on. How the drive is connected or what OS the drive used to be used for does not change the fact that you’re running the program under Windows 7, and doesn’t alleviate the need for a setup program to be run for many applications.


  11. Does it work for online gaming programs? Since it doesn’t have limitations on how many hardwares I can install it on, and logging in process comes up after the program starts running..? If specific game type is required to know, it’s mmorpg.

  12. Actually Ive installed several games on my external and they run fine from different computers i hook it up to. Relatively new games like Cod4 – Modern Warfare for instance.

  13. all of my program files are installed on alternate drives. just in case my windows wants to crap on itself. which it did after 3 years and 2million files (literally) later. Upon angering myself, I tried something odd, I did a tiny lil fresh install on a junk HDD, and added my other windows library’s, directory’s to it, and BAM! everything worked again. I BS you not. RAGE3D, Crysis1,warhead,and 2. Rfactor, Abelton live,, Reason, AVA. All of the programs that I was dreading to re install worked. Some random programs would say cant find yadda file, but if that was the case, just use the original .exe on that drive to launch it. *just make a short cut to it and move it to where you like. :D

  14. Do you think I dare chance it? I want to put my e mail programme on my external HD for the very reasons that LaTrice said. My awful HP desktop after 4 or 5 new motherboards and the HD finally was even corrupted and I lost all my years of EVERYTHING! I love Incredimail (I know many people don’t) anyway. I really want to try to put it on my external drive, note it does NOT give you the choice of what drive you want to install it on. And it puts it’s files for folders places I can not find anymore. That would be the main thing the folders files that take up so much of my HD space. But the whole programme needs to be on my external drive. Do you recommend putting all my WINDOWS files from C:/WINDOWS onto the external drive? Is that what it needs? Now does that mean COPYing them or transferring them? I don’t think my C:/ drive will operate without having them on it will it? So who ever posted they put the WINDOWS directory on their ext. HD and all the programs worked was not totally clear. I DO want to give it a try. I have my emails all over 4 different programmes and can’t find a thing. Thank you very much for your time in considering this request. Antoinette

  15. @Antionette
    That sounds very scary! External drives can also break, so even if you go to all the trouble to do that… you are still risking everything. Seems like you’d do better to try to find the source of the computer problems (poor ventilation, dust, dirt, electric surges?), and also do regular backups. No matter which drive goes out you won’t lose everything if you do not have it in one place.

    You should start by watching Leo’s backup webinars. That will give you a good foundation in backups, and an idea of how to move forward:

    Backup Webinar


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