[Resolved] Unable to resize screen

[maccas28]

I've seen other posts about this but I am having no luck. Also, I'm relatively new to VM's so bear with me.

I've got a MacOS host, and running a Windows 10 guest. In the VM, under View > Virtual Screen 1, all resizing options are greyed out.
I haven't installed the Guest Additions because it seems like they are already there. In VirtualBox, under Storage, SATA Port 1 has VBoxGuestAdditions.iso selected (even though I didn't install that, I think it may have come from the Windows 10 ISO installation file?).

EDIT: I realised that I installed the Guest Additions by going Device > Insert Guest Additions CD image, so that's where it came from. Anyway, I restart VirtualBox and the resize options are still greyed out.

Can someone help me out please? Many thanks.

[mpack]

"Insert Guest Additions CD" inserts the CD. It doesn't necessarily install the Guest Additions, not if your guest OS has CD autorun disabled.

If your Guest Additions are installed then there should be a small VirtualBox logo in the notifications area in the right side of the guest taskbar. Hover over that icon to get the GAs version. No logo means GAs not installed - so navigate to the CD drive inside the guest and run the GAs installer.

Remember to eject the CD when you're done: you don't want future VirtualBox updates to replace ISO images that are still mounted in VMs.

[maccas28]

Thanks mpack, that has worked.

I didn't realise you had to install the guest additions inside the guest OS, I thought it was on the VM. Thanks again!

[socratis]

Marking as [Resolved] then...

BTW a search for "unable to resize screen site:forums.virtualbox.org" could have saved you plenty of time...

[mpack]

I didn't realise you had to install the guest additions inside the guest OS, I thought it was on the VM.

A VM is just a simulation of hardware. It has no "magic powers", so there is very little it can do that physical hardware can't do. In particular, your hardware does not install software for you, though hardware signals (like a disk insertion signal) may prompt some OS's to install software, if they are configured that way.

When considering how something works in a VM, you won't go far wrong if you first consider how it works in a physical machine.