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virtualbox/doc/manual/en_US/user_KnownIssues.xml
Daniel Baumann df1bda4fe9
Adding upstream version 7.0.20-dfsg.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
2025-06-22 09:56:04 +02:00

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<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd"[
<!ENTITY % all.entities SYSTEM "all-entities.ent">
%all.entities;
]>
<chapter id="KnownIssues">
<title>Known Limitations</title>
<sect1 id="ExperimentalFeatures">
<title>Experimental Features</title>
<para>
Some &product-name; features are labeled as experimental. Such
features are provided on an "as-is" basis and are not formally
supported. However, feedback and suggestions about such features
are welcome. A comprehensive list of experimental features is as
follows:
</para>
<itemizedlist>
<listitem>
<para>
Hardware 3D acceleration support for Windows, Linux, and
Oracle Solaris guests
</para>
</listitem>
<listitem>
<para>
Hardware 2D video playback acceleration support for Windows
guests
</para>
</listitem>
<!-- <listitem>
<para>
PCI passthrough (Linux hosts only)
</para>
</listitem>-->
<listitem>
<para>
Mac OS X guests (macOS hosts only)
</para>
</listitem>
<listitem>
<para>
ICH9 chipset emulation
</para>
</listitem>
<listitem>
<para>
EFI firmware
</para>
</listitem>
<listitem>
<para>
Host CD/DVD drive passthrough
</para>
</listitem>
<listitem>
<para>
Support of iSCSI using internal networking
</para>
</listitem>
<listitem>
<para>
Using &product-name; and Hyper-V on the same host
</para>
</listitem>
</itemizedlist>
</sect1>
<sect1 id="KnownProblems">
<title>Known Issues</title>
<para>
The following section describes known problems with this release
of &product-name;. Unless marked otherwise, these issues are
planned to be fixed in later releases.
</para>
<itemizedlist>
<listitem>
<para>
The macOS installer packages for &product-name; 7 currently do
not include the Internal Networking feature, which is
available on all other platforms. This will be addressed with
an update of &product-name; 7. For setups which depend on this
functionality it is best to keep using &product-name; 6.1.
</para>
</listitem>
<listitem>
<para>
Poor performance when using &product-name; and
<emphasis role="bold">Hyper-V</emphasis> on the same host. To
fix this, certain Windows features like "Hyper-V Platform",
"Virtual Machine Platform" and "Windows Hypervisor Platform"
must be turned off, followed by a host reboot.
</para>
<para>
Additionally, the Microsoft Device Guard and Credential Guard
hardware readiness tool might have to be used in order to turn
off more features. For example, by running the following
command:
</para>
<screen>.\DG_Readiness_Tool_vX.X.ps1 -Disable -AutoReboot</screen>
<note>
<para>
Disabling Device Guard and Credential Guard features will
have an impact on the overall security of the host. Please
contact your Administrator beforehand regarding this.
</para>
</note>
</listitem>
<listitem>
<para>
The following <emphasis role="bold">Guest SMP (multiprocessor)
limitations</emphasis> exist:
</para>
<itemizedlist>
<listitem>
<para>
<emphasis role="bold">Poor performance</emphasis> with
32-bit guests on AMD CPUs. This affects mainly Windows and
Oracle Solaris guests, but possibly also some Linux kernel
revisions. Partially solved for 32-bit Windows NT, 2000,
XP, and 2003 guests. Requires the Guest Additions to be
installed.
</para>
</listitem>
<listitem>
<para>
<emphasis role="bold">Poor performance</emphasis> with
32-bit guests on certain Intel CPU models that do not
include virtual APIC hardware optimization support. This
affects mainly Windows and Oracle Solaris guests, but
possibly also some Linux kernel revisions. Partially
solved for 32-bit Windows NT, 2000, XP, and 2003 guests.
Requires the Guest Additions to be installed.
</para>
</listitem>
</itemizedlist>
</listitem>
<listitem>
<para>
<emphasis role="bold">NX (no execute, data execution
prevention)</emphasis> only works for guests running on 64-bit
hosts and requires that hardware virtualization be enabled.
</para>
</listitem>
<listitem>
<para>
<emphasis role="bold">Guest control.</emphasis> On Windows
guests, a process started using the guest control execute
support will not be able to display a graphical user interface
<emphasis>unless</emphasis> the user account under which it is
running is currently logged in and has a desktop session.
</para>
<para>
Also, to use accounts without or with an empty password, the
guest's group policy must be changed. To do so, open the group
policy editor on the command line by typing
<command>gpedit.msc</command>, open the key <literal>Computer
Configuration\Windows Settings\Security Settings\Local
Policies\Security Options</literal> and change the value of
<literal>Accounts: Limit local account use of blank passwords
to console logon only</literal> to Disabled.
</para>
</listitem>
<listitem>
<para>
<emphasis role="bold">Compacting virtual disk images is
limited to VDI files.</emphasis> The <command>VBoxManage
modifymedium --compact</command> command is currently only
implemented for VDI files. At the moment the only way to
optimize the size of a virtual disk images in other formats,
such as VMDK or VHD, is to clone the image and then use the
cloned image in the VM configuration.
</para>
</listitem>
<listitem>
<para>
<emphasis role="bold">OVF import/export:</emphasis>
</para>
<itemizedlist>
<listitem>
<para>
OVF localization, with multiple languages in a single OVF
file, is not yet supported.
</para>
</listitem>
<listitem>
<para>
Some OVF sections like StartupSection,
DeploymentOptionSection, and InstallSection are ignored.
</para>
</listitem>
<listitem>
<para>
OVF environment documents, including their property
sections and appliance configuration with ISO images, are
not yet supported.
</para>
</listitem>
<listitem>
<para>
Remote files using HTTP or other mechanisms are not yet
supported.
</para>
</listitem>
</itemizedlist>
</listitem>
<listitem>
<para>
Neither <emphasis role="bold">scale mode</emphasis> nor
<emphasis role="bold">seamless mode</emphasis> work correctly
with guests using OpenGL 3D features, such as with
Compiz-enabled window managers.
</para>
</listitem>
<listitem>
<para>
The RDP server in the &product-name; extension pack supports
only audio streams in format 22.05kHz stereo 16-bit. If the
RDP client requests any other audio format there will be no
audio.
</para>
</listitem>
<listitem>
<para>
Preserving the aspect ratio in scale mode works only on
Windows hosts and on macOS hosts.
</para>
</listitem>
<listitem>
<para>
On <emphasis role="bold">macOS hosts</emphasis>, the following
features are not yet implemented:
</para>
<itemizedlist>
<listitem>
<para>
Numlock emulation
</para>
</listitem>
<listitem>
<para>
CPU frequency metric
</para>
</listitem>
<listitem>
<para>
Memory ballooning
</para>
</listitem>
</itemizedlist>
</listitem>
<listitem>
<para>
<emphasis role="bold">macOS/ARM64 (Apple silicon) host
package</emphasis>
</para>
</listitem>
<listitem>
<para>
<emphasis role="bold">Mac OS X guests:</emphasis>
</para>
<itemizedlist>
<listitem>
<para>
Mac OS X guests can only run on a certain host hardware.
For details about license and host hardware limitations.
See <xref linkend="intro-macosxguests" /> and check the
Apple software license conditions.
</para>
</listitem>
<listitem>
<para>
&product-name; does not provide Guest Additions for Mac OS
X at this time.
</para>
</listitem>
<listitem>
<para>
The graphics resolution currently defaults to 1024x768 as
Mac OS X falls back to the built-in EFI display support.
See <xref linkend="efividmode" /> for more information on
how to change EFI video modes.
</para>
</listitem>
<listitem>
<para>
Mac OS X guests only work with one CPU assigned to the VM.
Support for SMP will be provided in a future release.
</para>
</listitem>
<listitem>
<para>
Depending on your system and version of Mac OS X, you
might experience guest hangs after some time. This can be
fixed by turning off energy saving. Set the timeout to
"Never" in the system preferences.
</para>
</listitem>
<listitem>
<para>
By default, the &product-name; EFI enables debug output of
the Mac OS X kernel to help you diagnose boot problems.
Note that there is a lot of output and not all errors are
fatal. They would also show when using a physical Apple
Macintosh computer. You can turn off these messages by
using the following command:
</para>
<screen>$ VBoxManage setextradata <replaceable>VM-name</replaceable> "VBoxInternal2/EfiBootArgs" " "</screen>
<para>
To revert to the previous behavior, use the following
command:
</para>
<screen>$ VBoxManage setextradata <replaceable>VM-name</replaceable> "VBoxInternal2/EfiBootArgs" ""</screen>
</listitem>
<listitem>
<para>
It is currently not possible to start a Mac OS X guest in
safe mode by specifying the <option>-x</option> option in
<literal>VBoxInternal2/EfiBootArgs</literal> extradata.
</para>
</listitem>
</itemizedlist>
</listitem>
<listitem>
<para>
<emphasis role="bold">Oracle Solaris hosts:</emphasis>
</para>
<itemizedlist>
<listitem>
<para>
USB support on Oracle Solaris hosts requires Oracle
Solaris 11 version snv_124 or later. Webcams and other
isochronous devices are known to have poor performance.
</para>
</listitem>
<listitem>
<para>
Host Webcam passthrough is restricted to 640x480 frames at
20 frames per second due to limitations in the Oracle
Solaris V4L2 API. This may be addressed in a future Oracle
Solaris release.
</para>
</listitem>
<listitem>
<para>
No ACPI information, such as battery status or power
source, is reported to the guest.
</para>
</listitem>
<listitem>
<para>
No support for using wireless adapters with bridged
networking.
</para>
</listitem>
<listitem>
<para>
Crossbow-based bridged networking on Oracle Solaris 11
hosts does not work directly with aggregate links.
However, you can use <command>dladm</command> to manually
create a VNIC over the aggregate link and use that with a
VM. This limitation does not exist in Oracle Solaris 11u1
build 17 and later.
</para>
</listitem>
</itemizedlist>
</listitem>
<listitem>
<para>
Neither virtio nor Intel PRO/1000 drivers for
<emphasis role="bold">Windows XP guests</emphasis> support
segmentation offloading. Therefore Windows XP guests have
slower transmission rates comparing to other guest types.
Refer to MS Knowledge base article 842264 for additional
information.
</para>
</listitem>
<listitem>
<para>
<emphasis role="bold">Guest Additions for OS/2.</emphasis>
Seamless windows and automatic guest resizing will probably
never be implemented due to inherent limitations of the OS/2
graphics system.
</para>
</listitem>
<listitem>
<para>
Some guest operating systems predating ATAPI CD-ROMs may
exhibit long delays or entirely fail to boot in certain
configurations. This is most likely to happen when an
IDE/ATAPI CD-ROM exists alone on a primary or secondary IDE
channel.
</para>
<para>
Affected operating systems are MS OS/2 1.21: fails to boot
with an error message referencing COUNTRY.SYS and MS OS/2 1.3:
long boot delays. To avoid such problems, disable the emulated
IDE/ATAPI CD-ROM. The guest OS cannot use this device, anyway.
</para>
</listitem>
</itemizedlist>
</sect1>
</chapter>