This will take quite some time, including several reboots of the Windows VM, but worked nicely in the end. Run the tool and select the “Upgrade now” option.It will need a couple of GB or so of disk space. Download Microsoft’s media creation tool to the 8.1 VM.Uninstall the Guest Additions from within the Windows 8.1 VM.Seems plenty of other people have had trouble doing this too, with some suggested solutions in this thread. Forcing an upgrade from Windows 8.1 to Windows 10 on OS X host in VirtualBox. That’s it – Windows can now see that full, larger disk.Īfter writing this I found a good similar page, with lots of screenshots and all – good resource if you need some extra guidance. The default setting should be fine, assuming that you want to make all the new space available to Windows. Right click the existing partition and select “Extend Volume”. In the disk management software, you will see a partition that is listed as “Unallocated”, that’s the space you just created in previous steps.Or just run diskmgmt.msc from the start menu. Select Manage, then go into the Storage->Disk Management section in the “Computer Management” app that opens. Right click on Computer in File Explorer.You also need to make Windows aware of it. In File Explorer you still do not see the new space.

This will take just a few seconds, the result will simply be a larger virtual disk.VBoxManage modifyhd “/path/to/your/vdi-files/.vdi” –resize Run just VBoxManage to get a list of all the options Run the command below, after adapting it to your needs.Open a terminal window (iTerm is a great replacement for OS X’s built in Terminal app.) and cd to the directory where your.Increasing size of a VirtualBox diskīefore even trying to upgrade from Windows 8.1 to 10, verify that the 8.1 VM’s disk has at least 10 GB free. Installing the VBox Guest Additions in the Windows 10 VM.īefore doing any of those steps, you might want to upgrade to OS X El Capitan, and to latest Virtual Box (5.x as of this writing).

Forcing the Windows 10 installer to run, even though its hardware compatibility checker says the VBox machine is not compatible with Windows 10.

Extending the Windows 8.1 virtual disk in VBox.

Turns out this is (of course.) not as easy as one would think – but still possible.

I am usually pretty ok upgrading to Apple’s latest OSs a week or two after their release – they are usually of good quality.Īs VirtualBox (“VBox”) also came out with their version 5 release, it was time to upgrade the Windows 8.1 virtual machine (“VM”) running in VBox, with OS X as host. Lots of OS upgrades lately, Windows went to Windows 10 and Apple to El Capitan.

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