None of the following warnings affect the build. Refer to relevant footnotes for further information.
-----
<pre>
dpkg-source: warning: extracting unsigned source package
</pre>

<pre>
dpkg-source: warning: extracting unsigned source package (anon-gw-anonymizer-config_5.0-1.dsc)
</pre>

<ref>
[https://forums.whonix.org/t/end-to-end-signed-debs-debsign-debsig-and-dpkg-sig/3446 end-to-end signed debs. debsign, debsig and dpkg-sig]
</ref>
-----
<pre>
Can not write log, openpty() failed (/dev/pts not mounted?)
</pre>
<ref>This is nothing to be concerned about; it only happens because commands are run inside chroot. Research of this "issue" indicates it is purely cosmetic.</ref>
-----
<pre>
[....] Your system does not have the CPU extensions required to use KVM. Not doing anything. ...[ FAIL ]
</pre>
<ref>KVM is installed as a dependency of the build dependency <code>libguestfs-tools</code>. KVM is not needed to build the actual images.</ref>
-----
<pre>
[....] Stopping VirtualBox kernel modules [ ok ].
[....] Starting VirtualBox kernel modules[....] No suitable module for running kernel found ...[ FAIL ]
invoke-rc.d: initscript virtualbox, action "restart" failed.
</pre>
<ref>This only means that VirtualBox cannot be started. VirtualBox kernel modules could not be compiled because the {{Code|linux-headers-$(uname -r)}} package was not installed prior to installing VirtualBox (before starting Whonix's build script). The build script does not start VirtualBox, hence does not affect the build. The build script only uses <code>VBoxManage</code> for creation of virtual machine description files and that tool does not need VirtualBox kernel modules.</ref>
-----
<pre>
WARNING: The character device /dev/vboxdrv does not exist.
	 Please install the virtualbox-ose-dkms package and the appropriate
	 headers, most likely linux-headers-486.

	 You will not be able to start VMs until this problem is fixed.
</pre>
<ref>This is caused by the same issue referenced above.</ref>
-----
<pre>
dpkg: warning: failed to open configuration file '/root/.dpkg.cfg' for reading: Permission denied
</pre>
<ref>This happens because <code>debuild</code> is run as user, not root. It is probably a bug in dpkg. Research of this issue reveals there are many similar bugs in dpkg.</ref>
-----
<pre>
sudo: unable to resolve host host
</pre>
<ref>
The hostname is changed intentionally to <code>host</code> inside the VM image. The cause is probably package <code>anon-base-files</code> postinst running <code>hostname "$my_host_name"</code> / <code>hostname host</code>. This change should only happen inside the change root <code>chroot</code>. This issue might be resolved by porting from <code>chroot</code> to <code>systemd-nspawn</code>, but it is not very important.
</ref>

Related forum topic: [https://forums.whonix.org/t/expected-build-warnings/129 Expected Build Warnings]