run parallels/windows from an external hard drive?

Discussion in 'Installation and Configuration' started by hobbesocrates, Jul 9, 2009.

  1. Hi,

    I just installed Parallels 3 with Windows XP on my MBP, but the HD is running out of space. I would like to be able to store all of the Windows files/Windows itself on my external HD and run parallels through that. Is this possible?

    Also, my ext. HD is currently formated for FAT 32, and the current size of the windows file is approx. 5 GB and therefore won't transfer. I was going to partition and reformat the drive, but I'm curious as to which format I would need to make the partition I'm going to put windows on. Will the "Mac OS Extended (Journaled)" work, or will windows not be able to write files on it (or is that done through parallels and therefore not a problem–which is my guess)?

    Thank you!
  2. desgael

    desgael Parallels Team

    As far as I know, as long as it is not FAT there should not be problem with copying large files. And since the virtual machine is, basically, the file on a Mac - Windows would not be affected.

    As for the external HD, since this is Parallels 3.0 I would suggest to copy the hard disk image, winxp.hdd, file (/Users/<username>/Documents/Parallels/<VM_name>/winxp.hdd) to the external HD and then create a new virtual machine using custom installation mode choosing "use existing hard disk image" option, when prompted, and pointing to that .hdd file.
  3. Thank you for your response.

    My ext HD is indeed a FAT32, so i guess i'm stuck unless i reformat it. But thanks for the confirmation that I can indeed run it from and ext source (I was afraid of reformatting my drive and its contents to no avail).
  4. I have a situation similar to this.

    I would like to take my current PC Hard drive, throw it into some kind of external hard drive case. Then hook it up to my imac via USB or firewire, and run windows and all the programs already installed on it from my mac.

    Is this possible with Parallels, and has anyone done exactly this in the past?

    Thanks in advance!
  5. I'm also looking to have my virtual machine on an external USB drive since my laptop drive space is limited.

    For my situation, I have PD4 on my laptop with a Windows XP install that is running out of space. I just ordered a new 500GB external USB drive that I'd like to move that virtual machine to and run off of. I also have a new copy of PD5 that I haven't installed yet that I'd like to run Windows 7 Ultimate with from the same external HD.

    I'm assuming that I'd have to install PD5 on the main/boot drive of the computer. Can I then install Windows 7 directly onto the USB external drive, or would I have to install it on the boot drive and then move it over (assuming you're able to run the vm externally?

    Another question comes to mind. Can I install the Windows 7 virtual machine on a networked drive that be accessed from all my computers running Parallels? (I apologize if these are newbie questions - it seems possible from reading the user manual, but I wanted to get confirmation from experienced users while I'm waiting for my new USB drive to ship.)

    Any helpful tips to setting this up properly? Thanks in advance for any help and insight!
  6. joevt

    joevt Kilo Poster

    Windows partitions on external drives should work in Parallels Desktop the same as partitions on internal drives do. Create a custom virtual machine, skip detection, and use the Boot Camp option to select the partition on the external USB drive.

    You can move a virtual machine in the Finder, then remove it from Parallels Desktop, then drag it from the new location to the Virtual Machine list to add it. You'll probably want to update it to a PD5 machine first.

    Parallels Desktop can create virtual machines on any connected networked or physical drive. Create a custom virtual machine and set the location to the other drive where you want the virtual machine to be saved. Parallels will warn you:
    "The virtual machine files are located either on a mounted volume or on a network share. Make sure this volume or network share is mounted to your Mac all the time the virtual machine is running. Otherwise, Parallels Desktop may work incorrectly and the data inside the virtual machine may become damaged."

    Only one person can use the same virtual machine at a time. Only one virtual machine can use the same virtual hard drive or Boot Camp partition at a time.
  7. I've been running my Parallels 5 VM off an external USB drive for months now without any glitch. In this way, all Windows-specific drive access such as Windows trying to swap to its virtual memory is happening on the external drive. This makes Parallels run faster on my (slow) MBAir, even though the VM hard disk traffic is somewhat throttled by the USB bandwidth.

    The file with my Virtual Machine ("Windows 7") sits on the external drive; the Parallels application sits on my internal drive. I just need to remember to plug the drive in when I start Parallels, otherwise Parallels will ask me where the VM lives :)
  8. Steps for setting up Windows, Linux on an external drive?

    Great post. It answers many questions I had in terms of my desire to run Windows, and Linux on an external drive as I need it.

    I am trying to understand if using an external drive is the way to go, given what I am trying to do. And I am looking for a step by step on how to set that up. Briefly, here is my situation:

    - I will never run Windows for any length of time; only brief bursts here and there to demo something.

    - I teach digital storytelling and simply want to show an audience that much of what you can do in iMovie can also be done in MovieMaker; so, all I want to do occasionally is hop into Windows (or Linux, if possible) to demo something; otherwise, I will not be using Windows.

    - I would like to do the same with Linux if possible, though this is less important.

    - I would like to have both XP and Windows 7 available if possible.

    - I have the latest MacBook Pro, and bought a LaCie external drive with 500 gigs and Firewire 400/800 capabilities (as well as USB, which I assume I would not use if I have Firewire)

    A few questions:

    - Based on this information, my more technical friends have advised me not to partition my hard drive on my Mac, but instead simply to use an external drive. Do you agree?

    - Is there a step-by-step sheet that will show me how to set this up?

    - Also, is there any problem if I simply don't plug in my external hard drive with Windows on it? I won't need it 99% of the time?

    Thank you for your advice.

  9. joevt

    joevt Kilo Poster

    Partitioning is only necessary if you're going to use Boot Camp. In that case, you would use Boot Camp Assistant and iPartition to create Windows XP, Windows 7, and Linux partitions on your internal drive, since you cannot boot Windows or Linux from an external USB or FireWire drive.

    You need to use Boot Camp only if Parallels Desktop does not perform well with MovieMaker.

    You only need an external drive if your internal drive won't have enough space for everything you want to use. FireWire 400 is faster than USB 2.0. A virtual machine takes 11 GB for Windows 7 (64 bit), 7 GB for Windows XP, and 7 GB for Linux. Additional apps will add to that. The virtual machine's virtual hard disk will expand to it's maximum size as you add files and apps to it. Documents can be stored outside the virtual machine's virtual hard disk using Parallels Shared Folders.

    You don't need to plug in your external drive unless you need to access a file that is located on the external drive.
  10. I don't see any need for you to partition your drive. Parallels' virtual hard disks are just (very large) files on the Mac. (Well, they're actually a bunch of files sitting together in a package inside the VM package, but for all practical purposes that doesn't matter - the VM package looks like a regular old file to you, and to the Mac's Finder). There is no benefit from partitioning in this case; on the contrary, keeping two large files on a (relatively) small partition will increase the likelihood, frequency, and amount of fragmentation.

    Whether you need to put the VM files on the internal drive or an external one really depends on

    _how much space you have on your Mac's hard drive
    _how large the virtual machines' hard drives are

    Example: If your Mac's internal drive is 320 GB, your virtual Windows drive is 32 GB, and your virtual Linux drive is 32 GB, you could keep both these VM's on the internal disk, using up about 64 GB of space there.

    Example 2: If your Mac's internal drive is 250 GB, your virtual Windows drive is 80 GB, and your virtual Linux drive is 60 GB, you might think about running these VM's from an external drive - after all, you'd eat up about 140 GB of your internal drive with just these two files (the Windows and Linux VM files).

    If you chose to put the VM files onto the external disk, there will be no problem if the external disk is not connected as long as Parallels isn't running. Even if you accidentally start Parallels (and have a VM set to autostart), it will simply tell you that it can't find the VM's files and just refuse to start that VM. You can then shut down Parallels and everything will be OK.

    To move a VM to an external disk,
    (1)connect the external drive to the Mac and copy the VM file to the external disk (Parallels should not be running).
    (2) Then start the VM off the external drive by double-clicking on the VM file that you've just copied. (Parallels might ask you if you've copied or moved the file; say "move" which will retain your virtual network card IDs to keep from having to re-authorize Windows).
    (3) If the VM then starts up and works normally, you can safely delete the VM files from the internal drive. (Well, you might want to make a backup first...)
    (4) done.

    Good luck!
  11. clarifying "virtual hard disk" size

    This is most helpful.

    Just making sure I understand something you said. You said, "The virtual machine's virtual hard disk will expand to it's maximum size as you add files and apps to it." This would seem to suggest that I am setting up a quasi-partition; perhaps not actually slicing up my hard drive, but setting a limit on how much room I need to reserve for each OS. If this is true, and I specify, say, 40 gigs, and use only 20 gigs, is the other 20 inaccessible for other things?

    Thanks you.
  12. joevt

    joevt Kilo Poster

    You are setting up a virtual hard disk file. You set how big the hard disk will appear to Windows. You can change this later. The amount of disk space the hard disk file takes on your Mac disk depends on the total size of the Windows files stored on the virtual hard disk.

    For example, if you create a 64 GB virtual hard disk, and install Windows XP on it, then the hard disk file will only be about 7 GB. It will grow in size as you add more apps and documents to it. All the while it will appear to Windows as a 64 GB hard disk. If you eventually need the hard disk to be bigger than 64 GB then you can change the size of the hard disk using the hard disk settings. Parallels will change the size of the disk without deleting any of the virtual hard disk's data.

    It is possible to create a 64 GB virtual hard disk even when your Mac disk contains less than 64 GB of free space because the hard disk file only requires enough space for the Windows apps and documents. However, problems will occur if Parallels tries to write more data to the disk when the Mac has no free disk space left.

    The space on your Mac hard disk that is not used by the virtual hard disk file is not reserved for the virtual hard disk file.
  13. Will this also work for the latest version?
  14. joevt

    joevt Kilo Poster

    Yes, in the latest version (I don't think there's a version where this doesn't work) you can move the .hdd out of the .pvm. In Parallels Desktop 6, create a new virtual machine with the "Continue without disc" option, and select "Customize settings before installation", then remove Hard Disk 1 (by selecting it and clicking the [-] button in the hardware list), then add (by clicking the [+] button) a new Hard Disk 1 that points to the .hdd.

    You could also just move the entire .pvm.
  15. Loading windows on thumb or external usb drive

    I have very little space on my hard drive - 1 gig.
    Can I load parallels on my hard drive, than load windows xp on my usb?
  16. Yes. However, with 1 Gig of free space on your hard drive, you'll be quite miserable. The Mac's hard drive needs some free space for virtual memory, and the Virtual Machine will need additional space for virtual memory. Your single Gig might easily be eaten up by this. I suggest you move other stuff to an external drive so you have at least 10 Gig free on the internal hard drive.
  17. external drive

    I will free up a few more gigs on my hard drive, but i do not need to load xp on my local drive, correct? I can load and install on an external hard drive and load Parallels on the mac, correct?
  18. yes, correct on both counts.
  19. If this is for XP and you're in a bind for space.. get yourself an 8-16GB USB key and you can install the VM to that. Format it as a standard Mac drive in Disk Utility, and when you create the new VM in Parallels just save to the USB key.
  20. Copy to and External HD

    I am wanting to the same as several others on this thread as I am out of room on my internal HD. I am running Parallels Desktop 6 with XP, which I had installed some time ago and have tried this. The hdd is name is slightly different and i don't know if this is relevant, Windows XP-0.hdd. I have tried to copy this to a WD 750 GB external HD which, is NTFS Format. But it doesn't want to copy i.e when I copy the paste is not available. I don't want to have to reinstall windows and office can you help.

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