virtualbox.org

My laptop screen has resolution 3840x2160 with scale 250%.

How to set host machine "Scale Factor" to 250% ?

It looks like I can't do it with GUI now, because it's limited to 200% and it's not enough...

• VBoxManage setextradata "<VM_Name>" GUI/ScaleFactor 2.5

For a more detailed explanation, see the original post: viewtopic.php?f=6&t=77731#p362196

Just don't go into your VM settings and press "OK" after that, or it will be lost. You can fix it again of course by re-entering the command above.

Thanks a lot! It helped

Glad you got it going. Marking as [Solved].

Because resolutions of a number of laptops reach 3K/4K, in which display scale factor in Windows is often set to 250%. However emulation of low resolutions (e.g. Display scale factor in Windows is 100%) is often needed, we should set Scale Factor in VM display settings to 250% in this condition. So I think that the max value of Scale Factor trackbar of Display settings of VirtualBox VM is a bit lower. We have to modify the .vbox config file. it will be perfect if max value of Scale Factor trackbar is increased to 400%,

I was thinking more of changing the range to 25-400, i.e. 4x smaller up to 4x larger. That should be plenty for the GUI I believe, from a stamp-sized zoom factor, up to "I can't see DOS anymore, too big" zoom factor.

But, merced, having said that, the next (or the one after that, I don't really know) version of VirtualBox is working on the HiDPI front. So, that scale factor in the GUI? It's gone! If you want to take a look (BACKUP FIRST), you can check out the Development snapshots (at the bottom of the page): https://www.virtualbox.org/wiki/Testbuilds. They are all are version 5.2.97 (that means development). Use at your own risk...