Starting a virtual device fails with "VBoxHeadless.exe - Application Error. [...] The memory could not be read."

On Windows, this error is typical with laptops with 2 GPUs: a low-profile integrated GPU, with low performances, and a high-profile discrete GPU.

To fix this, you need to force Windows to use the AMD/NVIDIA high-profile discrete GPU by default.

To do so, follow the instructions from this article: How to force Genymotion Desktop use the high performance discrete GPU on laptops?