GUI Problems? Time to Upgrade Qt

Having upgraded my FreeBSD system and VirtualBox, I found that VirtualBox does not work when invoked from the window manager’s menu. So, I tried running it from the command line, and got the following message:

/usr/local/lib/virtualbox/VirtualBox.so: Undefined symbol “_ZNK6QColor6darkerEi@Qt_5”

I tried to search the web for the cause, and found a link to a compatibility report including added symbols. My symbol was nott found there, but at least I got a clue about what I had to do: upgrade Qt5.

From some reasons I’m not notified that it’s time to upgrade my Qt5.

I found a great option for command pkg:I

pkg version| grep qt5

The output reveals the current version of a package, and if there are later versions; following is a typical output line:

qt5-printsupport-5.12.2 <

The less-then symbols indicates that there is a more recent version.

I started upgrading Qt5 packages, first qt5-core, then qt5-gui and saw a little progress: new undefined symbols. Finally, VirtualBox started working.

Another application affected by the failure to upgrade Qt5 is VLC , the famous media player from https://www.videolan.org

VLC does not show any error message, and you can run it from the command line with no problems. Specifying the path of the media device or file. For example by typing the command:

vlc cdda:///dev/cd0

if you want to listen to a compact disc.

Now, upgrading Qt5 has made VLC displaying its GUI window.

VirtualBox Failed to Save Settings

I recently installed VirtualBox configured internet connection to the internet for a virtual windows 7 machine I’ve installed using Vagrant, tried to setup USB, but got the following message: “Failed to save settings – Empty or null HostOnly interface name is not valid.”. Looking at the details, I saw the following “Result Code: E_FAIL (0x80004005) Component: NetworkAdapterWrapper …”.I don’t remember when I started to get that popup message. Couldn’t find any HostOnly adapter using the VirtualBox GUI. Finding the solution in the web is too hard. and I can’t find anything in the user guide either. But, one useful thing I know: in Linux and Unix-like system, I can find configuration files. They are usually found in directories whose names begin with ‘.’. followed by the program’s name or under “${HOME}/.config’ or directories created by the software. This time, the file was found in “${HOME}/VirtualBox VMs/<machine-name>”.
In this case: “${HOME}/VirtualBox VMs/windows7_default_1563689015423_90469/”. In this directory there are files with the suffix ‘.vbox’. They are XML files. In one of them, named “windows7_default_1563689015423_90469.vbox”, I find the following element:

        <Adapter slot="1" MACAddress="08002718154D" cable="true" type="82540EM">
          <DisabledModes>
            <InternalNetwork name="intnet"/%gt;
            <NATNetwork name="NatNetwork"/>
          </DisabledModes>
          <HostOnlyInterface name="VirtualBox Host-Only Ethernet Adapter #2"/>
        </Adapter>

Comment it out.
Problem solved.