Windows 8.1 guest crashes don't know why...

[Macmar]

Please I need help in solving a crashing issue on Windows 8.1 VM.

I have an iMac i5 4xxx- 8 GB RAM...as host.
I'm using the latest version of VB and so far I managed to instal Windows 8.1, GAs, USB ports, etc.

Everything seems to work fine except that every time I leave the computer alone for more than 15 or 20 min. Windows will crash by giving me a black screen. At that point, the only thing left for me to do, is to power off the VM. Shutdown signal will not work.
I also noticed that when using Windows VM, when I pass from desktop to start, the screen flashes a couple of times before doing so.

My power settings are set up to turn the display off after 10 min, and nothing else is selected.

I'm a beginner for I have no idea how to handle this

If anyone could help me I'll appreciate it.

I attach 2 logs below.

Thank you!

VBox.log.zip

Log 1

(22.31 KiB) Downloaded 6 times

VBox.log 2.zip

Log 2

(26.68 KiB) Downloaded 4 times

[mpack]

Does it still do it if you turn off 3D acceleration?

[ChipMcK]

Everything seems to work fine except that every time I leave the computer alone for more than 15 or 20 min.

Reads like a screen saver in the Guest at work, not a crash (and yes, it takes some doing to get a wake up). Check out the Guest's power management options.