Virtualbox has a single installer for windows that installs 32 bit application on 32 bit os and 64 bit application on 64 bit os. Is it any way to install 32 bit application on 64 bit windows Vista? I need this for COM automation, it's different for 32 bit and 64 bit.


The last VirtualBox release that didn't have the 32-bits and 64-bits versions bundled together was 2.1.
The 32-bits installer for version 2.1 can be downloaded from here.

If VirtualBox version 2.1 answers your need, then your problem is solved.

Otherwise, here are two ideas.

Idea #1: Install the old 32-bits VirtualBox version 2.1, then try to upgrade it to the latest.
Maybe the latest installer will prefer to upgrade the installed 32-bits version.

Idea #2: Download the VirtualBox sources and compile the 32-bits version (the Open Source Edition does not include an installer). That's maybe too much work, though

  • The 32 bit installer checks OS. I have reversed the MSI and removed all checks. But it still not install - seems it NEED to install some drivers that are not USB or NET related. And drivers are strict 32-bit or 64-bit - it's no way to install a 32-bit driver on 64-bit OS :(. – grigoryvp Oct 27 '09 at 20:18
  • Well, you might be able to under Windows 7 in XP mode, although more research is required for a more qualified answer. – harrymc Oct 27 '09 at 21:51
  • Yeah. But running virtual machine under another virtual machine is a bit of weird :). It wll be better for me to compile my QT-based application for 64-bit. Not an easy thing to do, but at last possible :). – grigoryvp Oct 30 '09 at 9:19
  • Running virtual machine under another virtual machine is ok if you have the memory for it. I don't understand why not install 64-bit VirtualBox and use a 32-bit VM - isn't this the same? – harrymc Oct 30 '09 at 10:34

The actual virtual machine monitor in virtualbox is a device driver in windows (exactly the same as VMware or VirtualPC). The Networking and USB components of virtualbox are also device drivers.

A 64bit os must have 64bit device drivers, so you cannot install x86 virtualbox on windows x64.


Is this COM automation of VirtualBox itself or of an app running in a VM? You can run a 32-bit OS on a VM running on 64-bit VirtualBox.

  • VBox itself. I want to control it and this requires inproc COM server. But i really don't want to create 2 versions of my app: 32 bit and 64 bit. I just want to install a 32 bit virtualbox on Vista 64 bit somehow :) – grigoryvp Oct 20 '09 at 13:50
  • Creating two separate versions usually just means creating two build targets and compiling against both. 32-bit and 64-bit shouldn't matter too much if you've been following the API. – Andrew Scagnelli Oct 23 '09 at 15:10

Have you tried this yet? Most 32 bit applications should run just find under Vista 64. If you run into any problems or if you have any specific problems errors, please update your question with more details.

  • It has ONE installer that is named "32bit/64bit". It automatically detects OS :(. I just don't know how to tell it to install specific version. – grigoryvp Oct 20 '09 at 13:49

Because of the low-level hooks that VirtualBox (or any VM software) makes into the host OS and its hypervisor, I don't think its possible to install the 32-bit version of the host software onto a 64-bit operating system.

Unfortunately, I can't find any documentation for VirtualBox's installer's command line switches, which might let you override the OS's bit-level detection. My guess is that there is just no way, for the reason I described above.


If all else fails...

The easiest way would to be to install Vista 32 bit as a guest OS. If you have a retail version, you should be able to use the same key for that without problem. Then you could program on that guest OS and install Virtualbox 32 bit on that guest OS. This first layer will be hardware accelerated an the second layer will then be software accelerated, now it's only dependent on the amount of memory you have available for this.

If you don't have the amount of memory needed or you need the second layer to be hardware accelerated then you would need to do a dual boot.

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