Windows guest in Virtualbox won’t increase the resolution beyond 1024×768… or any other for that matter

Here in Macedonia we have a saying (rough translation): The cure is cheap, but you have to know it.

The truth behind this saying was revealed to me this morning when I finally found out what I had to do to fix the problem I had with my Windows guest on VirtualBox. Turns out no matter what I did I couldn’t increase the guest resolution beyond 1024×768.
Now, the version of VirtualBox I currently have is 5.0.32 but this “remedy” would actually work with any version of this virtualization software.
These were the symptoms:

• It was a fresh box of Windows 7
• VirtualBox extension pack was installed
• VirtualBox guest additions was installed
• The Standard Microsoft display driver in Windows was replaced by the Oracle VirtualBox Graphics Adapter
• Maximum guest os resolution was 1024×768 and Display Properties won’t give me options higher then this
• “Auto-resize guest display” would only work when lowering the resolution, and after doing that, it won’t go up, not even to 1024×768
• Using “Virtual Screen 1 -> Resize to: (some resolution)” would also work one-way only…

Well… long story short, lost more then a few hours in searching what might be the problem, even provisioned a fresh box with no luck, and googling with a search phrase which has the following keywords included: “virtualbox linux host windows guest resolution” would give you a massive amount of results all mixed up for various problems where sometimes Linux is the guest, Windows is the host and then vice-versa… a real mess of problems and solutions mostly from the VirtualBox community forum.
And all I had to do is open VirtualBox File / Preferences, and in the Display settings set the “Maximum guest screen size” to “None”.

Fix problems with guest OS’s when you can’t increase the resolution even thou Guest additions is installed. This would be the likely reason.

As you can see there are three options there. The default (at least in my case) was “Hint”. And this is what the tool-tips say:

1. Automatic —  Suggest a reasonable maximum screen size to the guest
2. None — Do not attempt to limit the size of the guest screen
3. Hint — Suggest a maximum screen size to the guest

Such a noob!