1. Lumion 6.5 and newer:
Lumion 6.5 and newer require Windows 10.
Note that Lumion 11 requires Windows 10 version 1809 in order to run.
We recommend updating your Windows 10 to version 2004 or newer as it includes the Windows feature "Hardware-accelerated GPU scheduling" which improves the performance of Lumion in some Projects.
To see which version of Windows 10 you currently have installed, click on the Windows button and select Settings -> System -> About, to see the version number.
2. Lumion 6.3 and older:
If you're using Lumion 6.3 or older and need more than 4 GB memory for your scenes, we recommend that you run Lumion on Windows 7 (64-bit with at least SP1).
The reason is that Windows 8 and 10 do not allow older DirectX 9 applications (such as Lumion 6.3 and older) to use more than 4 GB graphics card memory for a given application - and no system memory either. On Windows 7, graphics card memory and system memory are not limited by the 4 GB cap when running older DirectX 9 applications such as Lumion 1.0-6.3.
Lumion 6.5 and newer are not affected by this cap and can use more than 4 GB memory on Windows 7, 8 and 10.