I tried to import that same OVA on a Windows 10 host running VirtualBox 5.2.24, and receive the following error when attempting to import the OVA:
Error in (line 113) -- Invalid value 'VBOXSVGA' in Display/@controller attribute.
F:\tinderbox\win-5.2\out\win.amd64\release\obj\VBoxAPIWrap\ApplianceWrap.cpp[387] (long __cdecl ApplianceWrap::Interpret(void)).
Result Code: E_FAIL (0x80004005)
Component: ApplianceWrap
Interface: IAppliance {8398f026-4add-4474-5bc3-2f9f2140b23e}
It appears that the OVF file has an additional attribute in the <Display> tag. If I unpack the OVA file into the OVF and VMDK file, I can patch the OVF file manually, and import the VM successfully:
--- Windows_10.ovf.bak 2019-01-23 07:09:03.000000000 -0700
+++ Windows_10.ovf 2019-01-24 16:37:15.675274600 -0700
@@ -110,7 +110,7 @@
<Memory RAMSize="4096"/>
<HID Pointing="USBTablet"/>
<Paravirt provider="Default"/>
- <Display controller="VBoxSVGA" VRAMSize="128"/>
+ <Display VRAMSize="128"/>
<VideoCapture screens="1" file="." fps="25"/>
<RemoteDisplay enabled="false"/>
<BIOS>
I'm wondering if either the documentation should be updated to state that importing an OVA in a VirtualBox version older than the version that produced the OVA is not supported, or if an option could be added to the VirtualBox 6 export option that says "generate VirtualBox 5.X compatible OVF", etc.? Or perhaps a subsequent 5.2.X build could ignore an unrecognized attribute for the Display controller?