Monday, 4 April 2016

Windows 7 WUAUSERV With High CPU & No Windows Updates

I have several PCs in my 'lab', a couple of laptops and two desktops. Of these one laptop and the two desktops run Windows 7 Professional. They are all fully licensed.

My main PC is working fine thankfully but both my laptop (a Sony Vaio from around 2011) and my 'spare' PC are suffering from high CPU load from WUAUSERV. This is actually the Windows Update service which provides automatic updating of security updates.

Thankfully both these machines are not turned on much and i have spent almost zero time to figure out what's wrong with them until now when i have tried to rid myself of these Windows Update issues.

My spare desktop used to be my main PC, it's a little old and decrepit it used to run Windows XP but i upgraded due to the EOL issues with XP. It's Windows 7 Professional 32bit.

As it had been my main PC i thought best thing i can do is just wipe it and re-install windows from scratch.

So this is what i did, the only remaining disk in the system was erased and Windows 7 reinstalled from new from the DVD.

After the usual installation of the odd driver i let windows pull down all the necessary windows updates since the creation of my install disk (Win7 SP1), which it did. Some updates installed and some failed. This is in fact normal in the first run of updates. After each reboot it would pick up a few more as dependences and pre-requisites for the updates change as they are installed.

This is where my issues arrived...

After the last run of updates i found the CPU hovering at 50% usage and the updater seems to be frozen checking for updates. The process is SVCHOST.EXE running WUAUSERV as shown in this screenshot:

I have 172 updates now installed on the system and is probably quite up to date right now (April 2016) but it's stuck now so i wont be seeing any new updates going forward. All i get now is 50% CPU load all the time and the Windows Update dialog shows only the following and never completes an update.

Now this issue is not new, indeed Microsoft have a couple of utilities available to diagnose problems like this. These are the Windows Update Troubleshooter and KB947821 aka System Update Readiness Tool (SUR).

The Windows Update Troubleshooter clears the Windows Update cache, logs etc and also checks a number of things that cause issues with updates.

The System Update Readiness Tool does some magic, to be honest i have no idea what it's doing but i think it goes deeper into checking for problems as it's a 200Mb+ installation compared with Windows Update Troubleshooter which is only a few 100Kb.

Both of these were run with no luck, SUR always exits with no reports so i have no idea what it may have looked for, found or tried to fix. The troubleshooter does have a report at the end which details it's unable to fix error 0x800F081F.

Looking around for this error shows it has a plethora of solutions meaning it's probably some generic failure mode without a specific cause. It is interesting though that this was a clean and freshly installed system. My only conclusion is this is caused by one of the updates arriving by the Windows Update mechanism.

I will continue my quest for a resolution and report back when i have some news.