virtualbox.org

I'm running Windows 7 on the virtualbox and I'm stuck with 32 bit colors. I'd like to get 8 bit colors or preferably even 256 colors.

The internet is full of guides how to increase the color depth but how can I decrease it?

I tried this:

VBoxManage.exe setextradata "MyWindows" CustomVideoMode1 1280x960x8

But it did nothing.

When I check "List All Modes" there's only 32 bit color resolutions.

When I check Monitor -> Colors, there's only 32 bit color on the list.

You can select any video mode you like inside the guest, using the Win7 display customization dialog.

8bit graphics predates Win7 by at least a decade, why would you want that? Never mind, your problem.

You'll get a warning from VirtualBox that graphics performance will be poor due to having to translate between host and guest graphics modes. The warning dialog has a "do not show" checkbox.

I unlocked the 256 color, 8 bit color, 16 bit color resolutions by uninstalling guest additions..

I'm pretty confused why would I even want guest additions if it reduces my options?

Guest Additions gives the usual user a lot of extra capability. Most folks are happy having 32-bit color and matching-host screen capabilities, as well as all the other stuff.
There may be unusual needs for certain users, but the choice is always available to use GAs or not, depending on requirements.

There's an option in the manager preferences which restricts graphics modes to what it considers a sensible subset. I'm not sure it affects color depth but you can change the preference and see.

As to the GAs, if you don't need good graphics performance then the GAs are probably moot anyway.