Explorer Using 25% CPU?

(PeteCresswell) · Nov 5, 2012

Last couple days, my response time for ordinary tasks like
opening folders, starting applications, and so-forth has
increased noticeably.

Looking at the numbers from both Task Manager and
Task-Manager-Like application, I see "Explorer.exe" taking 25% of
CPU.

I don't ordinarily look at this stuff, so maybe that's the way it
always is.... but in light of the response time thing, I have to
wonder if 25% is normal.

??

glee · Nov 5, 2012

(PeteCresswell) said:
Last couple days, my response time for ordinary tasks like
opening folders, starting applications, and so-forth has
increased noticeably.

Looking at the numbers from both Task Manager and
Task-Manager-Like application, I see "Explorer.exe" taking 25% of
CPU.

I don't ordinarily look at this stuff, so maybe that's the way it
always is.... but in light of the response time thing, I have to
wonder if 25% is normal.

What processor and how much RAM do you have? It's not unusual on a
single core to see that momentarily when you open a folder, and probably
more usage if you copy or move large amounts of files.... but if it is
at 25% for a large amount of time, that doesn't sound 'normal'. I don't
see hardly any increase in CPU usage from explorer when opening
programs. The program itself shows CPU usage as it opens.

I would check that you don't have a shell extension causing it. try
disabling all non-Microsoft shell extensions briefly, using this free
utility, and see if it makes a difference:
ShellExView - Shell Extension Manager For Windows
http://www.nirsoft.net/utils/shexview.html

You should also check for malware using MBAM and TDSSKiller.

Paul · Nov 5, 2012

(PeteCresswell) said:
Last couple days, my response time for ordinary tasks like
opening folders, starting applications, and so-forth has
increased noticeably.

Looking at the numbers from both Task Manager and
Task-Manager-Like application, I see "Explorer.exe" taking 25% of
CPU.

I don't ordinarily look at this stuff, so maybe that's the way it
always is.... but in light of the response time thing, I have to
wonder if 25% is normal.

??

It's probably 25% of a quad, so one core is "railed".
That's my guess. No, it's not normal. Head for a bomb shelter.

A few minutes ago, I had Explorer exit on "DEP error".
I'm heading down the ladder of my bomb shelter, right now...
WinXP SP3 x32.

Paul

Stefan Patric · Nov 5, 2012

Last couple days, my response time for ordinary tasks like opening
folders, starting applications, and so-forth has increased noticeably.

Looking at the numbers from both Task Manager and Task-Manager-Like
application, I see "Explorer.exe" taking 25% of CPU.

I don't ordinarily look at this stuff, so maybe that's the way it always
is.... but in light of the response time thing, I have to wonder if 25%
is normal.

??

Is the CPU at 25% continuously, all the time? Or is it intermittent?
Does it return after a reboot? The task running could be scheduled
system maintenance or some other innoxious thing. Or it could be malware.

Reboot the system and run the free versions of MalwareBytes' Antimalware
and SuperAntiSpyware. Then clean your system hard drive using disk
cleaner. Then test if the HD needs defragging.

If the problem returns, let us know.

Stef

BeeJ · Nov 6, 2012

(PeteCresswell) wrote on 11/5/2012 :

Last couple days, my response time for ordinary tasks like
opening folders, starting applications, and so-forth has
increased noticeably.

Looking at the numbers from both Task Manager and
Task-Manager-Like application, I see "Explorer.exe" taking 25% of
CPU.

I don't ordinarily look at this stuff, so maybe that's the way it
always is.... but in light of the response time thing, I have to
wonder if 25% is normal.

??

How much RAM?
How much virtual RAM?
How much crap in temporary folders?

CCleaner to clean out temp files.

MSCONFIG (at RUN) to see all the startup and services clogging up RAM.

You need at least 4G RAM (most used but not all). It's cheap.

(PeteCresswell) · Nov 6, 2012

Per Stefan Patric:

Is the CPU at 25% continuously, all the time? Or is it intermittent?
Does it return after a reboot? The task running could be scheduled
system maintenance or some other innoxious thing. Or it could be malware.

Continuous - all 4 processors, returns after reboot.

Paul · Nov 6, 2012

(PeteCresswell) said:
Per Stefan Patric:

Continuous - all 4 processors, returns after reboot.

If you're curious, when it is doing that the next time,
go to Task Manager, right-click on the Explorer one,
select "Set Affinity" from the context menu. If you've
got a Quad, there will be four boxes, all ticked.
Untick three of them, leaving Explorer to only run
on one core.

What you should see then, is "one core railed". That
one core should push its graph to 100%. So it really
is in a tight loop, on one core.

The scheduler bounces Explorer around from core to core,
giving the impression that all cores are moderately
occupied. But with Affinity, you may be able to demonstrate
what it's actually doing (railing one core). Using Affinity,
limits the options available to the scheduler.

You can't do that for everything, because some programs
really are multithreaded and capable of putting those
threads all on different cores. For example, my TV
tuner video program, runs on two cores. On a quad, it
would pick core 0 and core 3. It's actually in the
program code (picks the lowest and highest core numbers
as an arbitrary choice). If you then use Affinity, the
program still runs, but it might not be as smooth (jitter)
as it would be if left to its own plans. My suspicion is,
Explorer is single threaded, and that single thread wants
to run continuously, in a tight loop (railing one core).

Paul

glee · Nov 6, 2012

(PeteCresswell) said:
Per Stefan Patric:

Continuous - all 4 processors, returns after reboot.

This might be a helpful guide for troubleshooting your explorer issue:

The Case of the Intermittent (and Annoying) Explorer Hangs -
http://blogs.technet.com/b/markruss...intermittent-and-annoying-explorer-hangs.aspx

Have you checked for malware, and disabled shell extensions, yet?

Stefan Patric · Nov 6, 2012

Per Stefan Patric:

Continuous - all 4 processors, returns after reboot.

Boot computer into Safe Mode. Still doing it?

Stef

(PeteCresswell) · Nov 7, 2012

Per Stefan Patric:

Boot computer into Safe Mode. Still doing it?

No.

(PeteCresswell) · Nov 7, 2012

Per glee:

This might be a helpful guide for troubleshooting your explorer issue:

The Case of the Intermittent (and Annoying) Explorer Hangs -
http://blogs.technet.com/b/markruss...intermittent-and-annoying-explorer-hangs.aspx

Have you checked for malware, and disabled shell extensions, yet?

Rebooted in Safe mode, problem went away. CPU% for Explorer
didn't even register as a number.

Disabling shell extensions seems intimidating: from what I get
out of Googling, there are probably a *lot* of them.

I think the next step is the no-brainer stuff like MalwareBytes
and Kaspersky scan discs.

glee · Nov 7, 2012

(PeteCresswell) said:
Per glee:

Rebooted in Safe mode, problem went away. CPU% for Explorer
didn't even register as a number.

Disabling shell extensions seems intimidating: from what I get
out of Googling, there are probably a *lot* of them.

I think the next step is the no-brainer stuff like MalwareBytes
and Kaspersky scan discs.

Disabling only the non-Microsoft shell extensions with the utility I
gave you a link to, is very easy, takes about 10 seconds. If doing that
fixes the high usage, then you can enable half of what you disabled,
then half of that, to narrow down the extension that might be
responsible. It's a simple technique. I don't know what you are
googling, just try the utility. If disabling all non-Microsoft
extensions doesn't change the usage, you just re-enable them all with
the utility and move on.

(PeteCresswell) · Nov 7, 2012

Per glee:

Disabling only the non-Microsoft shell extensions with the utility I
gave you a link to, is very easy, takes about 10 seconds. If doing that
fixes the high usage, then you can enable half of what you disabled,
then half of that, to narrow down the extension that might be
responsible. It's a simple technique.

Mea Culpa. I missed the part about the utility.

But get this: after booting in Safe Mode, I re-booted in regular
mode and the problem had stopped. I definitely re-booted
multiple times before that and the problem persisted.....

Ran MalwareBytes anyhow, and it came up with something in my
D:\Temp called GiantSavings.exe and I killed it.... but this was
*after* the PC had rebooted without the problem, so I'm guessing
that GiantSavings.exe was not a player.

Maybe some kind of massive one-time file scan like the one
initiated when .NET 4 is installed?

I'll keep an eye on it and try the utility if the problem
resurfaces.

Thanks for all the useful info. My apologies for missing the
utility.

Stefan Patric · Nov 7, 2012

Per Stefan Patric:

No.