Upgraded windows 7 to windows 10, now cpu 99% all the time

[frappe]

I had a windows 7 guest which has always worked fine. I just upgraded it to windows 10 and now it's completely unusable. CPU is a constant 99%. I've done some researching and people suggest disconnecting the network, or pausing/unpause, and this does work for a few seconds but within 30 seconds or so the cpu usage has increased back to 99% again. Task Manager shows the same tasks when it's fast or slow; they just take up more cpu.

Host: ubuntu 16.04 64 bit. Core 2 quad CPU Q6600 2.4ghz. All 4 cores allocated to guest.
Guest: Was windows 7 pro 32 bit, now 10 pro.
Virtualbox 5.0.18 r106667 and the same version of guest additions.

The host is stable and ran windows 7 for years before. It runs another ubuntu vm fine. It's something to do with the upgrade to windows 10.

[socratis]

It's something to do with the upgrade to windows 10.

Yes, and it has nothing to do with the fact that Windows 10 is running on a VM. The same thing happens on a physical host. Windows, since 7, will take a lot of time at the beginning of its installation. The suspects are indexing and updates. You can use the Task Manager and/or ProcessExplorer (from SysInternals) to see which processes exactly are the ones to blame. Give it some time (like a day or so) and things will most probably calm down.

[mpack]

All 4 cores allocated to guest.

Well there you go. Why would leaving the host (where, incidentally, VirtualBox is running) with 0 CPUs be a good thing? What might one expect the result to be?

Plus what Socratis said.

If you want to continue this conversation then pPlease post a VM log file: with the VM fully shut down, right click it in GUI. Select "Show Log" and save "VBox.log" (ONLY) to a zip file. Attach the zip here.

[frappe]

All 4 cores allocated to guest.

Well there you go. Why would leaving the host (where, incidentally, VirtualBox is running) with 0 CPUs be a good thing? What might one expect the result to be?

Plus what Socratis said.

If you want to continue this conversation then pPlease post a VM log file: with the VM fully shut down, right click it in GUI. Select "Show Log" and save "VBox.log" (ONLY) to a zip file. Attach the zip here.

One might expect the result (of allocating all cores to the guest) to be the same for the windows 7 upgraded to windows 10 vm as it is for the ubuntu guest, and the various guests I've run on other boxes using both this and vmware player; sensible performance. It's not the host which is reporting 99% cpu usage and the host is still perfectly functional. (Are you saying you cannot run virtualisation on a single core host?) Having said that, i've never seen (for either vmware or virtualbox) any documentation which explains what approach should be taken here. They tend to suggest what look like extremely low amounts of ram be devoted to the guests; far less than you'd attempt to run a physical os on. If you know of sensible documentation in this area I'd definitely read it.

I'll leave the vm running for a day, now with 2 cores allocated to it, and see if it sorts itself out, before extracting logs.

Thanks for the advice.

[mpack]

Are you saying you cannot run virtualisation on a single core host?

Of course not, just as I'm not saying that you physically can't give all 4 cores to the VM on a 4 core host. Performance, however, would be terrible.