freezing guest os

[www1]

hi
Im using linux lubuntu 16.04 on guest and host machine, and using last version of vb
guest machine is for work
sometimes guest machine begin freeze without any actions, and I must shut down it
how can I fix it?

[mpack]

Minimum information needed for assistance.

[www1]

vb Version 5.1.26 r117224 (Qt5.5.1)
VBOXADDITIONS_5.1.26_117224
host lubuntu 16.04 23gb ram x64
guest lubuntu 16.04 12gb ram x64

[mpack]

You might want to look at the Discuss the 5.1.26 release topic. There is some discussion in there concerning 5.1.26 and VMs which are using AC'97 audio.

There is a regression in 5.1.26 which can cause VMs with AC'97 audio configured to crash. So far the problem has only been seen on Windows hosts, and it's somewhat random (which means that some users will see it almost all the time and other users almost never).

It isn't a perfect fit in that Michaln suspects that only Windows hosts are affected, but he did say "so far". You might want to test this: there are a couple of ways to do it, i.e. disable audio or configure Intel HD audio.

On a peripheral matter, you might also want to eject the VirtualBox GAs CD, as it isn't good practice to keep it mounted.