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Problem Deleting Prefetch data with CC Cleaner 2.30.113


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#1 OFFLINE pcumming

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Posted 24 April 2010 - 04:48 PM

I added to the OPTIONS INCLUDE to DELETE all prefetch files in C:\Windows\prefetch that are of file type *.pf, it did not delete any files. Also tried with no file type (ie, delete all files). Still no deletion.

I had already unchecked the "Delete old prefetch data" box. I then checked the box and it still did not delete any prefetch files.

Okay, so then I decided to try to delete ALL files in C:\windows\prefetch EXCEPT to EXCLUDE layout.ini which is the file that is always supposed be there else you will have to recreate it. Still did not delete any prefetch files.

HOWEVER, I noted the prefetch file names were similar to: IEXPLORE.EXE-2D97EBE6.pf, IPCONFIG.EXE-05D7908C.pf -- long file names. Not sure if this is relevant.

I did have the box checked for Customer Files and Folders.

Thanks for any help
Peter

#2 OFFLINE pcumming

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Posted 24 April 2010 - 10:06 PM

I posted in wrong section of forum. Sorry
In any event I found out by reading a few items on Google that if you select SECURE DELETE in CCleaner that it sometimes affects the deletion of files. If you use normal deletion then the prefetch files I selected with file type of *.pf will be deleted.

Peter

#3 OFFLINE Aethec

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Posted 25 April 2010 - 02:17 AM

Don't clean your Prefetch files.
  • Prefetch files only are a list of the libraries a program need, in order.
  • Prefetch files aren't loaded with Windows.
  • Prefetch files are very small.
  • Prefetch files don't use any memory, CPU cycles, or whatever.
  • The only moment where Prefetch files are used is when you launch a program.
Deleting Prefetch files will increase your applications's launch time.
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#4 OFFLINE Augeas

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Posted 25 April 2010 - 03:36 AM

Peter, just having the Delete old prefetch data box ticked is sufficient to delete old stuff. CC won't delete any entries until they are 14 days (or is it 10?) old, so on an active pc using a wide set of applications you might not see any deletions at all. If your prefetch folder has reached the limit then Windows will knock off the oldest unused entries for you.

I use a small set of applications, so my prefetch folder never approaches the Windows max of around 127 (can't remember the actual figure). Some prefetch files would never be cleared from my folder, so I have this option ticked. I know it's a piffling thing, but I do it, and I have about 35-40 prefetch entries at amy time.

Having unused stuff in the prefetch folder is quite revealing. They often contain a list of accessed data files, and this list gets amalgamated into Layout.ini (which can be huge, and is a quite interesting read!). Not only does Windows use this list to run a mini-defrag of all these files every few days, which I could quite easily live without, but every man and his dog can see what you've been up to.

#5 OFFLINE Aethec

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Posted 25 April 2010 - 05:08 AM

every man and his dog can see what you've been up to.

What do you mean ?
Prefetch files are named according to the exe they refer to, and they only contain DLLs paths. The only thing that could show something is if the exe's name has something special in its name ;)
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#6 OFFLINE Augeas

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Posted 25 April 2010 - 05:32 AM

If you look at Layout.ini using Wordpad you will see that it lists many user data files associated with the applications in the prefetch folder. They will usually be harmless, but there could be thingsIshouldnotlookat.jpg. Layout.ini, and the .pf files it is created from, can hold names of files long since deleted. It's no great problem, but somebody will worry about it.

#7 OFFLINE mr don

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Posted 26 April 2010 - 12:27 AM

Don't clean your Prefetch files.

  • Prefetch files only are a list of the libraries a program need, in order.
  • Prefetch files aren't loaded with Windows.
  • Prefetch files are very small.
  • Prefetch files don't use any memory, CPU cycles, or whatever.
  • The only moment where Prefetch files are used is when you launch a program.
Deleting Prefetch files will increase your applications's launch time.



That may be true, but clearing PF files from time to time is actually beneficial. When malware is set to load with windows, then you remove the malware, do you REALLY want it still set to load each time with windows, hogging CPU cycles trying to figure where that application is gone to so it can "load" it again?

Although PF claims to speed things up, in cases like these, it does the opposite.

Net effect of gain is reduced to practically 0 by the advent of malware & other problems.

Peace!

#8 OFFLINE Augeas

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Posted 26 April 2010 - 05:57 AM

Whilst I agree that it would be a good idea to clean the prefetch folder now and again (to get rid of dross and reduce prefetch defrag time), Windows does not use this folder to determine what is being loaded either at boot or any other time, so it can't reintroduce malware or any other baddie. As Aethec says, it's just a list.

#9 OFFLINE Alan_B

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Posted 26 April 2010 - 08:09 AM

I have no experience of a virus since my younger son left school and stopped bringing home copies of games on 5.25" floppy discs to run on my DOS v3.?? Luggable P.C.

I would like to think that if a P.C. is afflicted with malware,
it will be dealt with by experts that will not only regain functional control,
but will also scan through all the nooks and crannies for any residues.

I would be disappointed if they left in the prefetch a nasty residue.

Alan

#10 OFFLINE Aethec

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Posted 26 April 2010 - 09:44 AM

That may be true, but clearing PF files from time to time is actually beneficial. When malware is set to load with windows, then you remove the malware, do you REALLY want it still set to load each time with windows, hogging CPU cycles trying to figure where that application is gone to so it can "load" it again?

Although PF claims to speed things up, in cases like these, it does the opposite.

Net effect of gain is reduced to practically 0 by the advent of malware & other problems.

Peace!


No. Prefetch files are NOT loaded with Windows. Please read this : http://www.edbott.com/weblog/?p=743
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#11 OFFLINE Willy2

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Posted 28 April 2010 - 09:34 AM

Very interesting discussion.

Augeas,

If the contents of ""Layout.ini"" is bothering you then I have some good advice. Just delete the file and then force Windows to rebuild it. The result is that that file shrinks in size. The content is used for the mini defrag operation. When it contains less entries (i.e. directories and files that don't exist anymore) then the operation takes less time to complete. I forced Windows XP to rebuild that file as well and the size of the file shrank from 374 kB to a ""mere"" 94 kB.

The following article provides some very good information.
http://windowstipsan...-layoutini.html



#12 OFFLINE Augeas

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Posted 28 April 2010 - 09:52 AM

I did that Willy, and the contents (I can't recall the actual file sizes) were exactly the same as before. I believe that Windows builds Layout.ini from the existing prefetch files, so I would expect the contents to remain the same.

I do notice that if I delete a few prefetch files then Layout.ini shrinks in size quite quickly, so it is being dynamically managed by good old Windows.

#13 OFFLINE Willy2

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Posted 28 April 2010 - 12:30 PM

Augeas,

I closed all programs and windows, deleted all the files in the prefetch folder, restarted my computer and then forced Windows to rebuild ""Layout.ini"" again. The result was that that file was only 19 kB in size.

Aethec,

Using the information in the prefetch folder speeds up Windows but when the user has used e.g. Defraggler then that info has/can become worthless. Because the file has been moved to another place on the drive. Then Windows is forced to go through the entire directory tree structure and the MFT, in order to know where that file has been moved to. And that's a good reason to use Defraggler not too often.



#14 OFFLINE Aethec

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Posted 28 April 2010 - 02:24 PM

Using the information in the prefetch folder speeds up Windows but when the user has used e.g. Defraggler then that info has/can become worthless. Because the file has been moved to another place on the drive. Then Windows is forced to go through the entire directory tree structure and the MFT, in order to know where that file has been moved to. And that's a good reason to use Defraggler not too often.

I don't think so. Prefetch files contains path to data, not exact location on drive.
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#15 OFFLINE Augeas

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Posted 28 April 2010 - 03:24 PM

Augeas,

I closed all programs and windows, deleted all the files in the prefetch folder, restarted my computer and then forced Windows to rebuild ""Layout.ini"" again. The result was that that file was only 19 kB in size.

Ah Willy, what a difference a few words make!

#16 OFFLINE Willy2

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Posted 28 April 2010 - 04:23 PM

Augeas,

Yes, I was surprised as well



#17 OFFLINE Willy2

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Posted 14 May 2010 - 01:27 AM

Augeas,

I think that the internal defrag operation which takes place every three days (Windows XP) uses the MRU (Most Recent Used) lists in the registry and perhaps information from the ""recent"" folder as well to re-build or to add information to ""Layout.ini"". In the registry Windows XP keeps track which folders and/or files the user has opened.

See e.g. my last post in this thread
http://forum.pirifor...showtopic=27868

So, wiping the 1) prefetch folder, 2) MRU lists in the registry, 3) ""Recent opened"" folder regurlarly does prevent ""Layout.ini"" from filling with obsolete info and that speeds up the internal defrag process. Because then it contains less information that needs to be processed.