Further update - making some progress.
In VirtualBox manual, sec. 4.2.1.1, about two-thirds of the way through the section, the manual states that one may “. . . choose VBoxWindowsAdditions.exe from the CD/DVD drive inside the guest to start the installer.” So I did that and now the files in C\program_files\Oracle etc. have been updated to the matching version (5.0.22r108108). So that worked and didn’t blow up the system.
Now the logs read slightly differently. VBoxSVC.log:
VirtualBox XPCOM Server 5.0.22_SUSE r108108 linux.amd64 (openSUSE Buildservice) release log
00:00:00.001507 main Log opened 2016-07-02T22:56:44.267290000Z
00:00:00.001509 main Build Type: release
00:00:00.001513 main OS Product: Linux
00:00:00.001514 main OS Release: 4.1.26-21-default
00:00:00.001515 main OS Version: #1 SMP PREEMPT Mon Jun 13 13:32:30 UTC 2016 (294632f)
00:00:00.001537 main DMI Product Name: System Product Name
00:00:00.001543 main DMI Product Version: System Version
00:00:00.001642 main Host RAM: 5957MB total, 5431MB available
00:00:00.001646 main Executable: /usr/lib/virtualbox/VBoxSVC
00:00:00.001647 main Process ID: 3441
00:00:00.001647 main Package type: LINUX_64BITS_GENERIC (OSE)
00:00:00.106867 nspr-2 Home directory: '/root/.config/VirtualBox'
00:00:00.107049 nspr-2 Loading settings file "/root/.config/VirtualBox/VirtualBox.xml" with version "1.12-linux"
00:00:00.107904 nspr-2 Successfully initialised host USB using sysfs
00:00:00.111918 nspr-2 NAT: resolv.conf: nameserver 192.168.1.1
00:00:00.111985 nspr-2 HostDnsMonitor: old information
00:00:00.111994 nspr-2 no server entries
00:00:00.112000 nspr-2 no domain set
00:00:00.112003 nspr-2 no search string entries
00:00:00.112007 nspr-2 HostDnsMonitor: new information
00:00:00.112010 nspr-2 server 1: 192.168.1.1
00:00:00.112014 nspr-2 domain: home
00:00:00.112018 nspr-2 search string 1: home
00:00:00.112025 nspr-2 HostDnsMonitorProxy::notify
00:00:00.114023 nspr-2 VD: VDInit finished
00:00:00.114120 nspr-2 ERROR [COM]: aRC=NS_ERROR_FAILURE (0x80004005) aIID={0eb668d2-495e-5a36-8890-29999b5f030c} aComponent={SystemPropertiesWrap} aText={Cannot determine default Guest Additions ISO location. Most likely they are not available}, preserve=false aResultDetail=0
00:00:00.117962 nspr-2 Loading settings file "/root/VirtualBox VMs/m5-vm2/m5-vm2.vbox" with version "1.14-linux"
00:00:11.976818 nspr-2 Load [/usr/lib/virtualbox/ExtensionPacks/Oracle_VM_VirtualBox_Extension_Pack/linux.amd64/VBoxHostWebcam.so] rc VINF_SUCCESS
00:00:12.200486 nspr-3 ERROR [COM]: aRC=VBOX_E_IPRT_ERROR (0x80bb0005) aIID={f30138d4-e5ea-4b3a-8858-a059de4c93fd} aComponent={SessionMachine} aText={Saved screenshot data is not available (VERR_NOT_SUPPORTED)}, preserve=false aResultDetail=0
00:00:12.227276 nspr-2 ERROR [COM]: aRC=VBOX_E_IPRT_ERROR (0x80bb0005) aIID={f30138d4-e5ea-4b3a-8858-a059de4c93fd} aComponent={SessionMachine} aText={Saved screenshot data is not available (VERR_NOT_SUPPORTED)}, preserve=false aResultDetail=0
Note that the third event from the end (00:00:00.11.976818) states that the extension pack loaded successfully. But there are three errors.
The last two seem to have something to do with a screenshot that’s not available. I’m going to put those aside for now, as I don’t believe they will preclude or degrade the VM’s operation.
The first one is puzzling, because the iso is in what I believe to be the default location for the configuration files: /$user/.config/VirtualBox. And the machine’s .vbox xml file shows this address(see ):
<?xml version="1.0"?>
<!-- ** DO NOT EDIT THIS FILE. etc.
. . .
-->
<VirtualBox xmlns="http://www.innotek.de/VirtualBox-settings" version="1.14-linux">
<Machine uuid="{cab7b222-509b-417b-bb03-5b5bb38234bb}" name="m5-vm2" OSType="Windows7_64" snapshotFolder="Snapshots" lastStateChange="2016-07-02T22:56:57Z">
<MediaRegistry>
<HardDisks>
<HardDisk uuid="{3790b482-03fa-42e9-bf2a-f01852a19721}" location="win7 Clone1-disk1.vdi" format="VDI" type="Normal"/>
<HardDisk uuid="{45fbe6ed-99e6-4384-8bab-7fb614ecb27a}" location="/z/linux13-1/root/VirtualBox VMs/WindowsXP Clone1/WindowsXP Clone1.vdi" format="VDI" type="Normal"/>
</HardDisks>
<DVDImages>
<Image uuid="{11962368-06c0-4e9d-9f35-bf4448741447}" location="/root/.config/VirtualBox/VBoxGuestAdditions_5.0.22.iso"/>
</DVDImages>
<FloppyImages/>
</MediaRegistry>
<ExtraData>
<ExtraDataItem name="GUI/LastCloseAction" value="PowerOff"/>
<ExtraDataItem name="GUI/LastGuestSizeHint" value="1657,1078"/>
<ExtraDataItem name="GUI/LastGuestSizeHint1" value="1689,1114"/>
<ExtraDataItem name="GUI/LastNormalWindowPosition" value="133,29,1657,1131"/>
<ExtraDataItem name="GUI/LastNormalWindowPosition1" value="2006,29,1689,1171"/>
<ExtraDataItem name="GUI/LastScaleWindowPosition" value="2,23,1596,1128"/>
<ExtraDataItem name="GUI/LastVisibilityStatusForGuestScreen1" value="true"/>
<ExtraDataItem name="GUI/RestrictedRuntimeDevicesMenuActions" value="HardDrives"/>
<ExtraDataItem name="GUI/RestrictedRuntimeMachineMenuActions" value="SaveState,PowerOff"/>
<ExtraDataItem name="GUI/SaveMountedAtRuntime" value="yes"/>
<ExtraDataItem name="GUI/ScaleFactor" value="1"/>
<ExtraDataItem name="GUI/StatusBar/IndicatorOrder" value="HardDisks,OpticalDisks,FloppyDisks,Network,USB,SharedFolders,Display,VideoCapture,Features,Mouse,Keyboard"/>
</ExtraData>
<Hardware version="2">
<CPU count="1" hotplug="false">
<HardwareVirtEx enabled="true"/>
<HardwareVirtExNestedPaging enabled="true"/>
<HardwareVirtExVPID enabled="true"/>
<HardwareVirtExUX enabled="true"/>
<PAE enabled="false"/>
<LongMode enabled="true"/>
<HardwareVirtExLargePages enabled="false"/>
<HardwareVirtForce enabled="false"/>
</CPU>
<Memory RAMSize="512" PageFusion="false"/>
<HID Pointing="USBTablet" Keyboard="PS2Keyboard"/>
<HPET enabled="false"/>
<Chipset type="PIIX3"/>
<Boot>
. . .
</Boot>
<Display VRAMSize="128" monitorCount="2" accelerate3D="true" accelerate2DVideo="false"/>
<VideoCapture enabled="false" screens="18446744073709551613" horzRes="1024" vertRes="768" rate="512" fps="25" maxTime="0" maxSize="0"/>
<RemoteDisplay enabled="false" authType="Null" authTimeout="5000">
<VRDEProperties>
<Property name="TCP/Ports" value="3389"/>
</VRDEProperties>
</RemoteDisplay>
<BIOS>
<ACPI enabled="true"/>
<IOAPIC enabled="true"/>
<Logo fadeIn="true" fadeOut="true" displayTime="0"/>
<BootMenu mode="MessageAndMenu"/>
<TimeOffset value="0"/>
<PXEDebug enabled="false"/>
</BIOS>
<USB>
. . .
</USB>
<Network>
. . .
</Network>
<UART/>
<LPT>
<Port slot="1" enabled="false" IOBase="0x378" IRQ="7"/>
</LPT>
<AudioAdapter controller="HDA" driver="ALSA" enabled="true"/>
<RTC localOrUTC="local"/>
<SharedFolders>
<SharedFolder name="D" hostPath="/z/D" writable="true" autoMount="true"/>
<SharedFolder name="F" hostPath="/z/F" writable="true" autoMount="true"/>
</SharedFolders>
<Clipboard mode="Bidirectional"/>
<DragAndDrop mode="Bidirectional"/>
<IO>
<IoCache enabled="true" size="5"/>
<BandwidthGroups/>
</IO>
<HostPci>
<Devices/>
</HostPci>
<EmulatedUSB>
<CardReader enabled="false"/>
</EmulatedUSB>
<Guest memoryBalloonSize="0"/>
<GuestProperties>
. . .
</GuestProperties>
</Hardware>
<StorageControllers>
<StorageController name="IDE" type="PIIX4" PortCount="2" useHostIOCache="true" Bootable="true">
<AttachedDevice passthrough="true" type="DVD" port="0" device="0">
<Image uuid="{11962368-06c0-4e9d-9f35-bf4448741447}"/>
</AttachedDevice>
<AttachedDevice passthrough="true" type="DVD" port="0" device="1">
<HostDrive src="/dev/sr0"/>
</AttachedDevice>
</StorageController>
<StorageController name="SATA" type="AHCI" PortCount="2" useHostIOCache="false" Bootable="true" IDE0MasterEmulationPort="0" IDE0SlaveEmulationPort="1" IDE1MasterEmulationPort="2" IDE1SlaveEmulationPort="3">
<AttachedDevice nonrotational="true" type="HardDisk" port="0" device="0">
<Image uuid="{3790b482-03fa-42e9-bf2a-f01852a19721}"/>
</AttachedDevice>
</StorageController>
</StorageControllers>
</Machine>
</VirtualBox>
But the file also identifies the Windows XP clone that shows up the as the VERR_FILE_NOT_FOUND error that triggered this inquiry (see HardDisk uuid="{45fb,etc., the entry immediately above the guest additions iso).
I suspect it is simply a matter of deleting the image, but from where?