virtualbox.org

While in the Main manager Preferences-> network -> host-only tab click the green + and set it up with the defaults. It should do this automatically but if not I will provide you a guide to use.
Now I need to ask why you think you need to use vagrant. Is it for a real reason or do you think it is just sexy or that it might make your life easier?

1. Well, this is fun. I restarted VirtualBox, went to Preferences-> network -> host-only tab, clicked the green & got this message:

Failed to create the host network interface.

VBoxNetAdpCtl: Error while adding new interface: failed to open /dev/vboxnetctl: No such file or directory.

Result Code: NS_ERROR_FAILURE (0x80004005)
Component: HostNetworkInterfaceWrap
Interface: IHostNetworkInterface {455f8c45-44a0-a470-ba20-27890b96dba9}

Not sure if this is helpful, but here's the vbox.log file:

2. As to my choice of vagrant, I'm starting as a WordPress developer & want to use the same workflow I used when I managed/developed/maintained document production systems: a local install of the system for development & online stages for testing, UAT & prod. I tried AMPP & was dissatisfied with it, then read & heard from a number of WordPress developers that VVV was the way to go.

00:09:03.502271 VMMDev: Guest Log: BIOS: Boot : bseqnr=1, bootseq=0231
00:09:03.502492 VMMDev: Guest Log: BIOS: Boot from Floppy 0 failed
00:09:03.502751 VMMDev: Guest Log: BIOS: Boot : bseqnr=2, bootseq=0023
00:09:03.503231 VMMDev: Guest Log: BIOS: CDROM boot failure code : 0003
00:09:03.503429 VMMDev: Guest Log: BIOS: Boot from CD-ROM failed
00:09:03.503714 VMMDev: Guest Log: BIOS: Boot : bseqnr=3, bootseq=0002
00:09:03.504236 VMMDev: Guest Log: BIOS: Boot from Hard Disk 0 failed
00:09:03.505576 VMMDev: Guest Log: No bootable medium found! System halted.

This log shows that there is no bootable media meaning that you must have removed the Install media from the virtual drive and in fact had not actually installed the guest. Most Linux installs are live meaning that they will boot and run but you must actually install them to be able to save any work done.

Doing a search for "failed to open /dev/vboxnetctl:" shows this is a vagrant issue of sorts but usually affects MAC OS X

If it were me I would completely remove vagrant, and VirtualBox deleting the already installed guests folders to remove all traces of vagrant control files. Then after a reboot of the host install VirtualBox and then Mint but do not install vagrant. Then we can test the host-only interface without the problem of vagrant. If this all works then you can install vagrant and try again.

completely remove vagrant, and VirtualBox deleting the already installed guests folders to remove all traces of vagrant control files. Then after a reboot of the host install VirtualBox and then Mint but do not install vagrant.

Done. It works: Are there any other steps I need to perform before we move on to vagrant?

Thanks.

I would check to see if the host only adapter was created as it should have been by default.

Keep in mind that you now have a working version of VirtualBox with a working guest. When you install vagrant if you encounter any issues you will need to contact them and if and when they tell you this is a VirtualBox issue you know better.

Now you see why we do not support vagrant installs.

Perry--

In re the host-only adapter, I believe the two attached screenshots indicate that it was: Frankly, while I do indeed see your point, what I see more than anything else is that this whole mess was my own fault. I had no idea what I was doing when trying to install LInux on VirtualBox before--a classic case, I'm not proud to admit, of RTFM. Since VVV includes installation & configuration of the guest in its script, I hadn't had to face the issue before. The cherry on top was stupidly clicking OK to upgrade VirtualBox late last week, which clearly screwed up my installation of VVV. I'd forgotten all about it, which is why this is the first time you're hearing about it, but it came to me last night while I was doing the reinstalls.

Anyway, having unburdened myself, shall I assume that it's OK to move on to installation of VVV?

Thanks.