Suddenly CPU usage reach 100%

[Lorenzo_]

My Host is Windows 7 64 bit. I have 2 guests:

• Windows XP sp3
• Windows 7 32 bit

I used them for months without any problem. 2 months ago those guests began having a problem: sometimes after 10 minutes, sometimes after some hour, CPU reach 100% usage and never go down. Sometime on the W7 guest, sometime on the XP guest. When both are runnig, the problem appear on both vm almost simultaneously. I' ve tried a lot of solutions searching on the web, but nothing solved this. The problem appears when I use one of those VM and even when both are running. I tried:

• to change antivirus (security essential > trend micro) (vm w7 and xp)
• to remove antivirus (vm w7 and xp)
• to scan guests and host with Combofix (vm w7 - nothing found - and xp: removed 3/4 dll)
• to scan guests and host with Malwarebytes (vm w7 and xp) (nothing found)
• to set video memory to 32, 64 and 128 MB (vm w7 and xp)
• to move the W7 vm on an eSata HDD , then to an USB HDD (vm W7)
• to remove nested paging (vm W7 and XP)
• to install APIC (vm W7)
• to change VirtualBox Version (4.2.10 > 4.2.12 > 4.2.14)

It seems that it has something to do with Network load:

• once, disconnecting a Cisco VPN, the CPU load came back to normal values;
• disabling the Network Device (from Machine > Devices > Network) end leaving the vm on Pause for some minute the CPU load came back to normal values; after this I can set the network device as it were before the problem without other issues. This works EVERY time.

I tried to work with bridge card and with NAT, but even this can't prevent the problem.

​https://forums.virtualbox.org/viewtopic.php?f=2&t=56176

[Lorenzo_]

Log of the Win XP vm: the problem appeared > removed network device > paused for 10 minutes > resumed.

[Lorenzo_]

Unplugging network cable from the host can also solve the problem in a few minutes.

[Hartsan]

I have Ubuntu 12.04 LTS 64bit host running VirtualBox v4.3.10 and Windows 7 Ultimate 64bit guest. I have had this same issue with all the previous VirtualBox versions. I have allocated 2 CPU cores (out of 6 (+6 for hyperthreading)) for the Windows host.

With Ubuntu host 'htop' command I can typically see 200% CPU load on the Windows 7 virtual machine.

I tried to disable network like the solution above suggested and rebooted the virtual host. Still it took all the 200% CPU. I even tried to start another Linux-based VM as some other issue suspected, wouldn't help.

I verified my automatic Windows 7 updates were already disabled. I couldn't find "Automatic Updates" from the Services list, but there was "Adobe Acrobat Update Service".

Stopping the "Adobe Acrobat Update Service" cause the CPU load drop from constant 200% to around 19%-21%. Note that the virtual network adapter was already and is still disabled.

At this point, re-enabling the network adapter causes CPU load of the Windows host start varying between 17%-40%. Still a lot less than 200%.