Why does Windows 7 Explorer Consume 99% CPU

[ChrisGreaves]

(Months later: Please see this post)

Club.myce suggests tweaking the registry keys for AVI.
I don’t have those keys (specifically) but I tried deleting the higher level (risky!) to no avail.

Answers.Microsoft suggests FLV files might be the problem.
I don’t have any FLV files, or if I do, not more than ten, yet the CPU consumption occurs in a great many folders at the oddest times.

Social.TechNet suggests “Always show icons, never thumbnails.”.
Done that!

Support.Microsoft suggests that the problem might be corrupted files.
If so I have an awful lot of corrupted files that don’t seem to faze MSWord, MSExcel, ChkDsk etc.

Toms hardware suggests trying “Uncheck the line that loads Windows Image Acquisition”.
Done that.

Any other ideas?

The PrtScr image below shows what I see for 50 seconds after I left-click on the folder “Appl” (which folder holds all the downloaded zip files for non-DOS applications installed on my system. 1,682 files in 240 folders, since you ask, and no, not greatly enlarged since my XP days, and no, WinXP never demonstrated this sluggishness when opening a folder.

Then I click on the "+" sign to expand the folder and get another delay (I forgot to time it) of about 20 seconds or so.

The grey status line creeps across the top of the screen, and this is typical for many folders, seemingly at random.
I have “Good Days” when I seem to experience no delays at the system, even if I drive it from 4am to 8pm; then other days I want to hurl the lot out the window (glass variety)

(signed) “Wit’s End” of Toronto

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[HansV]

Does the Processes tab of the Task Manager, sorted descending on CPU usage, provide a clue?

[ChrisGreaves]

Does the Processes tab of the Task Manager, sorted descending on CPU usage, provide a clue?

Not so much a clue as a gong-ringing sledge-hammer.
I'll render a PrtScr next time it happens, assuming I can squeeze enough resources to load MSPaint.

The Processes tab show Explorer.exe at the top of the list with 99%, sometimes plummeting (hah!) as low as 95%.

I've got fed up enough to wander outside onto the balcony while this is going on, and watering the geraniums.

With my tears.

P.S. I forgot to mention that there's TWO repasts at The Montreal Deli⁽¹⁾ for the successful resoluter of this problem. It's been costing me, roughly, ten minutes a day since Dec 22 2010, and mountains of frustration.

⁽¹⁾ Tell Amar you want him to cook the hamburger, liver and onions, or pork chops the way he does for me.

[ChrisGreaves]

Does the Processes tab of the Task Manager, sorted descending on CPU usage, provide a clue?

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There we go!
Or rather, "will go", once Explorer is done.
This was taken after a reboot, nothing else loaded (except MSPaint and Task Manager)

The status bar is creeping slowly towards the right, immediately above 'View".
Explorer was drifting between about 94% and 99%; I captured 99% because i wanted to test my reflexes (grin)
I had loaded MSPaint and TaskManager before clicking on the folder.
Interestingly enough, same folder, T:\Appl\, which means that there's a strong chance that I can reproduce this at will.

(I'm out of the office for 5 hours or so ...)

[viking33]

Chris,
My vote goes along with MS in thinking corrupt file(s) in the T:\Appl folder.
It's total size of 3.19G is fairly sizable and Windows Explorer has to scan through all of these files to show them in the screen tree.
Chkdsk won't look for corrupt files, just bad sectors, etc. Word and Excel aren't doing anything with these files at the time that explorer is scanning them.
The only thing I could suggest ( if you have a Thumb Drive or a spare external HD ) would be to try moving ( not copying ) a batch of these files off the T drive, a group at a time, then see if the time is improved. Hit and miss I know but it seems everything points to something there on the T drive itself.

[JoeP]

Is Windows 7 SP1 installed?

Joe

[ChrisGreaves]

Is Windows 7 SP1 installed?

Thanks Joe.
I suspect Not.
I DO NOT have automatic updates turned on.
I think I ought.
The PrtScr seems to suggest that I do not have SP1.
(1) When did it come out?
(2) Have you reason to think it fixes my problem?

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[ChrisGreaves]

... try moving ( not copying ) a batch of these files off the T drive, a group at a time, ...

Hi Bob.
Good Thinking, and before I upgrade to SP1 (Please see my reply to Joe) ...

We can do better than that.
I already have the folder backed up, but tonight I can just ZIP the lot, then delete the folder for a few days.
It's not material that I use daily.

[HansV]

(1) When did it come out?

SP1 was released in February (of 2011); although there is no guarantee it will solve your problem, it's a good idea to install it anyway.

[viking33]

... try moving ( not copying ) a batch of these files off the T drive, a group at a time, ...

Hi Bob.
Good Thinking, and before I upgrade to SP1 (Please see my reply to Joe) ...

We can do better than that.
I already have the folder backed up, but tonight I can just ZIP the lot, then delete the folder for a few days.
It's not material that I use daily.

Right, you'll have to check to see what other hotfixes MS needs before you do the SP1 upgrade. If you don't auto update, there will probably be a lot of security updates in line before you should do the SP1 download.

The reason I said to move a group of files at a time, was to try to isolate just which one(s) were the bad actors. Maybe you could zap the lot and then restore a few at a time, then try the explorer route to catch the problem files, if there are any.

[ChrisGreaves]

(1) When did it come out?

SP1 was released in February (of 2011); although there is no guarantee it will solve your problem, it's a good idea to install it anyway.

Thanks Hans.
I'm going to follow through with Bob's idea first - at least to the point of deleting the folders to see if that IS the cause of the problems - then schedule a host of Automatic Updates.

[ChrisGreaves]

The reason I said to move a group of files at a time, was to try to isolate just which one(s) were the bad actors. Maybe you could zap the lot and then restore a few at a time, then try the explorer route to catch the problem files, if there are any.

The good old "Binary Chop". Got it.
I figured that since I hardly ever use them, by deleting them all I'd get a fast answer to the question of whether the corruption was in there or not.

I now feel that it won't be a fast answer; I went to look in T:\Batlap, a collection of BATch files, and it too is sluggish.
So if more than one folder contains corrupted files I'll be deleting most of my system!

[ChrisGreaves]

The reason I said to move a group of files at a time, ...

Hi Bob.

I zipped the folder, saved the Zip, deleted the folder, rand for 24 hours (admittedly I was out most of the day).
Same problem in at least five other foldrs, so I'm inclined to think it's not a corrupted folder, unless all my folders are corrupt, which I call a "corrupted system", and usually fix by reloading Windows to the C: drive.

I am now wading through Updates. (Please see my upcoming response to Hans).

[ChrisGreaves]

SP1 was released in February (of 2011); ... it's a good idea to install it anyway.

OK, Thanks again, Hans.
I am now in the process of Clicking "Restart now" a million times ...
(later)
Done!
Now let's see how this runs for the remainder of the day.
I cannot believe that any of the 7 outstanding optional updates should affect Explorer's ability to load folder information.

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[ChrisGreaves]

SP1 was released in February (of 2011); ... it's a good idea to install it anyway.

Touch Wood.
24 hours running and no repeat of the problem ...

[HansV]

Good to hear that!

[ChrisGreaves]

Good to hear that!

I might actually start to enjoy Win7 now!
P.S. that is TWO 26ox bottles of Swan Lager from the most beautiful capital city in the world.

[ChrisGreaves]

Good to hear that!

I think I've worked out why I had updates turned OFF.
It's because Win7 reboots my system automatically after installing updates, and I don't necessarily want that.
I think I'll go back and try "d/l but don't install", and leave installations until the weekend.


I leave some long jobs running overnight and/or don't want to wait for my boot sequence jobs to run first thing when i rise.

[ChrisGreaves]

The grey status line creeps across the top of the screen, and this is typical for many folders, seemingly at random.

It's early days yet, but late last night I implemented the fix mentioned at Windows Seven Forums "Windows 7 - Explorer SLOW on large folders".
This morning, without a reboot, everything goes swimmingly.
My biggest beef about Win7 was that it took 60 seconds to display the contents of a folder.
I think impatience at this delay has contributed to some of my other problems.
(I know, I know, I should grow up ...)

(Next day). Nope.
Still sluggish on my drive T:, which is a TrueCrypt volume.
Today's task is to un-encrypt the drive and see if it is any faster.
This will involve two scenarios:

The drive is G:, and is an encrypted volume.
I had been assigning it the letter T: when mounting the drive with TrueCrypt.
My batch files refer to T:, and I don't want to change that (for now)
So I will use a DOS SUBST command as a temporary fix.

Scenario 1: Test access times on drive G: itself; if they are fast, then perhaps TrueCrypt was part of the problem

Scenario 2: If access to drive G: is fast, then I test access times on drive T:; if they are slow, then perhaps mapping a drive is part of the problem.