32 bit color mode error

[pmwaters]

I have a Windows 7 32 bit guest on a Win 7 64 bit host. When I start up the guest I get an error that says: "The virtual machine window is optimized to work in 32 bit color mode but the color quality of the virtual display is currently set to 24 bit. Please open the display properties dialog of the guest OS and select a 32 bit color mode, if it is available, for best possible performance of the virtual video subsystem."

I have installed guest additions, enabled 3d mode while installing GA in safe mode, and my video memory is set to 256 MB with 3D and 2D acceleration enabled. My display settings in the guest Windows OS show that the color settings are set to True Color (32 bit). However, I can test my color depth by going to lorem.php/mycolordepth.php, which shows my screen is set to 24 bit color mode.

The same test with the host machine verifies that it is in 32 bit color mode.

Normally I would just ignore the message since, as far as I know, the only difference between 24 and 32 bit is transparency. Unfortunately I need the 32 bit color mode for testing.

I've tried different variations of video memory, guest addition installations and enabling/disabling 3D and 2D video acceleration, yet can't seem to get the guest to actually display in 32 bit color - even though the video display settings in the guest control panel are set to True Color 32 Bit.

Anyone know what I could be doing wrong?

[mpack]

It just means that the guest is running in some more basic mode at the precise moment the warning was generated. The dialog includes a checkbox to stop it appearing again.

[pmwaters]

It just means that the guest is running in some more basic mode at the precise moment the warning was generated. The dialog includes a checkbox to stop it appearing again.

I thought that was the case too, but when I test the system when it is fully booted it is actually displaying in 24 bit mode. This is evident by the fact that transparent colors do not work, and verified with lorem.php/mycolordepth.php.

[mpack]

The message really warns you that there's a difference between the display modes in the guest vs the host, meaning that guest graphics data can't simply be blitted unchanged to the host, hence performance will be poor. As I already mentioned, the warning can be disabled if you don't care. Otherwise it's up to you to resolve.

Incidentally, while it is true that the spare byte is often used for transparancy, that isn't necessarily true. The main reason for using 32bits per pixel is so that each pixel is aligned on a dword boundary for performance reasons. I.e. I don't know why your host is not configured that way.

[hangerglide]

I've read quite a few msgs re this issue and this is the most current. This issue still seems to be ongoing. Is there any more info re what the issue is? I can always click the 'dont show this msg' in the dialog, but since mpack has indicated that can result in poor performance, I'd prefer not to. The guest is windows 7 x63, and per the display settings it says it at 32 bit. But I still get the warning at each vm start.

[mpack]

It's a warning. If you are satisfied that the the warning has already been actioned by you then go ahead and disable it.

[noteirak]

To be clear : your host and guest color depth is not the same. Virtualbox warns you of it, but it not an issue that Virtualbox can fix. You can choose to ignore the warning or configure your OSes properly so it matches

[hankejh]

I can report the same behavior with a Win7x64 guest on a Max OS X 10.8.5 host (MacBook Pro Retina 15).

I'm leaving the alert active in order to easily know if/when an update solves the problem and thus improves performance.

[BobC]

A little late, but in Windows 7, you can set it to 32 bit display by right clicking on the screen. Then click on "Screen Resolution". You will see "Advanced Setting about halfway down. Click on that. Then a "pop-up" box will appear and click on "Monitor" where you will see you can select 32bit True Color. However, you will still probably get the "error message" somewhat at Oracle needs to fix this. They also need to move the "Devices" to the main menu rather than waiting until you start the virtual machine, pressing F12 and rebooting - a rather convoluted way of changing ISOs when testing different OSes.

[mpack]

Oh no, not again...

somewhat at Oracle needs to fix this

First, it's a warning, not an error. Second, it's telling you something important that you need to fix, Oracle can't. Third, if you think the warning is inappropriate then there's a checkbox on the dialog to turn it off.

[son cenabre]

Hi,

I read this thread when i encountered a problem with the color depth of my vbox win7 changed after i added a virtual hard disk. vbox changed it from 32 bit to 24 bit. then my programs cannot run anymore. i solved the problem when i increase the machine base memory from 512 to 2GB.

all my programs are back to normal now. It SOLVED the problem.

I hope this will help you.

PS. this is my first post.

[mpack]

vbox changed it from 32 bit to 24 bit.

No, it didn't. VirtualBox has no way to affect the color depth used by a guest OS, except by failing to support the color depth requested. And VirtualBox definitely supports 32bit colors.

Naturally if you starve the guest OS of graphics RAM this could have lots of weird effects on guest graphics, but I don't see how changing the ordinary RAM setting would do anything. More likely IMHO, resetting your VM is what fixed your problem, which you had to do in order to change the RAM setting.

[gilbertpilz]

I am running VirtualBox 5.1.16. I have a VM running Windows 7 with the Extension Pack and Guest Additions installed. I have configured the VM with 128 MB of video memory. When I try to change the color resolution to 32 bits, Windows 7 shows "1900 by 1200, High Color (16 bit), 60 Hertz" as the maximum color resolution possible at 1900 x 1200. Is this a Windows issue or a VirtualBox issue. How can I get to 32 bit color at 1900 x 1200? Does the "Auto-resize Guest Display" option have anything to do with this?

[socratis]

How much vRAM have you allocated to your guest? Have you installed the Guest Additions (GAs)? Both of these questions can be definitively answered if you:

• Follow a "start the VM from cold-boot" / "observe error" / "shutdown the VM" cycle.
• With the VM shut down completely (not paused or saved), right-click on the VM in the VirtualBox Manager and select "Show Log".
• Save only the first "VBox.log", ZIP it and attach it to your response (see the "Upload attachment" tab below the reply form).