Delete all prefetch files

CCleaner for Windows CCleaner Windows Suggestions
21
Rubbish. Maybe you're not familiar with XP. I see CCleaner as ticked for cleaning out 'Old Preftech data'. Mustn't be working??

I run Windows XP on several machines and have observed the self-cleaning. It seems to require layout.ini to update after 128 pf files have accumulated and a subsequent reboot. Because layout.ini only updates periodically, it may take up to 3 days for this to transpire.

If you Google "Windows XP prefetch 128", you'll find numerous references regarding the self-limiting behaviour from reliable sources.

One good reason to empty the prefetch folder is if a pf file or layout.ini is corrupt. I have encountered one machine where there was an error message to that effect and execessive pf files seemed to have accumulated. After deleting everything including the layout.ini, it seemed to self-maintain.

If you check Vista Help for "prefetch", you'll find an article stating "The prefetch folder is self-maintaining, and there's no need to delete it or empty its contents." AFAIK that means it is also self-limiting but I don't know if the size limits and parameters are the same as XP.

22

Contrary to popular belief, Prefetch is there for a reason. The entre idea of prefetch is to pre-load components for programs that you use often to speed up their launch. Prefetch does not contain any "vital" components for running programs, but is actually just an optimization that microsoft built into the operating system. Deleting the prefetch data has a SLIGHTLY positive effect on boot time, but slows down the launch of your commonly used programs. Deleting all prefetch data does more harm than good, although microsoft does say that it can sometimes have a slightly detrimental effect on EWF performance, but this is not a consideration for almost any PC users. The space that you (temporarily) save is insignificant, but the decrease in performance is noticeable.

I just ran some program opening benchmarks on my laptop, which measured the opening (time from execution start to window appearing) speed for three of my programs (twice per program), deleted all prefetch data, rebooted, and ran again. The Result was an average of a 19.627% drop in program opening speed.

Although I admit I did not do this in a perfectly controlled environment (such as a fresh virtual machine), this is a significant enough change for me to say that deleting all prefetch data is a mistake.

If you still believe that prefetch is a waste of space, you can disable it by following Microsoft's instructions here.

This sounds fine, as long as prefetch is working good & all your programs are there. But just as many times as it helps, it is also detrimental to performance. What happens, is EXE are regularly removed, uninstalled, renamed, deleted, etc & the prefetch folder attempts to load something that no longer exists, slowing the boot process down while windows checks for that program & no longer finds it.

Additionally, when you have malware & the malware is prefetched too, you do not really want that to happen, do you? Faster loading malware? Also, what happens when you remove malware, but the prefetch entries still exist? Hmmm?

Adding the ability to totally remove the Prefetch folder will NOT harm anything. At worst, the layout will be recreated, & users will be able to delete all the entries so they can get rid of malware that is already set to prefetch, in addition to missing EXE files they have deleted/moved/uninstalled.

There may be "downsides" to removing the prefetch folder such as more time booting, but there are so many benefits, I see no reason it should not be included!

23

Did you really need to bring back a 1-year-old thread ?

Anyway, deleting the content of the Prefetch folder is a bad idea. See One more time : Do not clean out your Prefetch Folder by Ed Bott.

24

Hey everyone please note the people you are quoting are long gone. . . that said

RoninV has a good question. . . though maybe s/he should start a new thread for it.

25

The SuperFetch has nothing to do with the Prefetch. http://en.wikipedia.org/wiki/Windows_Vista_I/O_technologies#SuperFetch

26

It's my understanding that superfetch is similar to prefetch, as far as idea. Superfetch loads frequently used apps into memory, so they load faster upon user input. It has that same 'trace' feel as prefetch. Should the user not be able to empty it, or at least have CCleaner delete older listings?

27

It's my understanding that superfetch is similar to prefetch, as far as idea. Superfetch loads frequently used apps into memory, so they load faster upon user input. It has that same 'trace' feel as prefetch. Should the user not be able to empty it, or at least have CCleaner delete older listings?

There are no SF listings. It justs loads commonly used libraries and apps into memory - probably using layout.ini, the same as Prefetch uses.

One more time : Emptying. Prefetch. Is. Not. A. Good. Idea.

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Clearly, opinions vary when it comes to the manipulation of prefetch. My original inquiry was regarding CCleaner lack of a feature that manipulates superfetch, since it has (still) one for prefetch.

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Clearly, opinions vary when it comes to the manipulation of prefetch. My original inquiry was regarding CCleaner lack of a feature that manipulates superfetch, since it has (still) one for prefetch.

You can't manipulate SuperFetch, unless you know where it loads its data - and I think it uses layout.ini since it's much easier than rebuilding another index.

30

I think "Old Prefetch Data" means "files in C:\Windows\Prefetch\ older than X days"....

Anyway, cleaning Prefetch is not a good idea and will not improve your computer's performance (even if lots of sites are saying disabling Prefetch is good)

I think Microsoft programmers know better what is good and what is not than most of the users.

Just like emptying temp files may NOT be good for most users. Did you know? If you LEAVE the temp files in your computer, Internet Explorer actually uses them for a good reason. DO NOT delete the temp files! Every website you go to is stored on the computer in the temporary files directory! This makes it faster, especially if you are using dial-up, because the computer will then call up the stored webpage in it's cache & load it from the harddisk instead of having to check the web for the page! I think Microsoft programmers know better what is good & what is not than most of the users! DO NOT, DO NOT, DO NOT delete the internet explorer files folder, or you risk LOSING all those stored webpages so that windows can load them faster next time!

Besides, doesn't windows auto clear the cache after a preset limit?

This of course, is just my way of creating a parody of the prefetch file problem to show you that technically, the temporary files CCleaner cleans could be treated exactly the same way you are treating the prefetch files.

I would love if it deleted them all. I have a fast machine, a few extra seconds never hurt anyone, & in addition, windows will re-generate the ones I use pretty rapidly!

Of course, if you still insist, I also insist on keeping all my internet explorer temporary websites folder full, because you never know how many seconds it will save to just load the website from the hardisk instead of the internet!

Hahaha!

31

Just like emptying temp files may NOT be good for most users. Did you know? If you LEAVE the temp files in your computer, Internet Explorer actually uses them for a good reason. DO NOT delete the temp files! Every website you go to is stored on the computer in the temporary files directory! This makes it faster, especially if you are using dial-up, because the computer will then call up the stored webpage in it's cache & load it from the harddisk instead of having to check the web for the page! I think Microsoft programmers know better what is good & what is not than most of the users! DO NOT, DO NOT, DO NOT delete the internet explorer files folder, or you risk LOSING all those stored webpages so that windows can load them faster next time!

Besides, doesn't windows auto clear the cache after a preset limit?

This of course, is just my way of creating a parody of the prefetch file problem to show you that technically, the temporary files CCleaner cleans could be treated exactly the same way you are treating the prefetch files.

I would love if it deleted them all. I have a fast machine, a few extra seconds never hurt anyone, & in addition, windows will re-generate the ones I use pretty rapidly!

Of course, if you still insist, I also insist on keeping all my internet explorer temporary websites folder full, because you never know how many seconds it will save to just load the website from the hardisk instead of the internet!

Hahaha!

Temp files != IE's cache. I never said emptying the cache would increase performance ; the main point of cleaning it is not having lots of data that will never be used again because you won't visit the associated website again.

However, deleting Prefetch files has no positive effect at all. They are not loaded with Windows, they do not use RAM, they do not use CPU cycles, or whatever. http://www.edbott.com/weblog/?p=743

:rolleyes:

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Temp files != IE's cache. I never said emptying the cache would increase performance ; the main point of cleaning it is not having lots of data that will never be used again because you won't visit the associated website again.

However, deleting Prefetch files has no positive effect at all. They are not loaded with Windows, they do not use RAM, they do not use CPU cycles, or whatever. http://www.edbott.com/weblog/?p=743

:rolleyes:

The only reason he listed, was performance going down slightly. I really do not care. What is 1 extra second? I just know if I got trash, no matter if it is 1kb, or even 1 file, if it is trash, I want it gone. Windows will regenerate the files easily & quickly enough, so I do not care if having a PF file saves me 1 second because it preloads components needed for the files you are using. I just want them gone, gone, gone!

I have tested with & without prefetch, & even with prefetch turned off. At least, if not totally clearing the PF folder, at least give us the option to totally turn PF off without having to manually edit reg keys or use 3rd party apps. I do not like the PF folder, & I suppose that I never will. It is useless to me. Besides, with IE, over time you collect thousands or even millions of webpages, so windows has to spend a few seconds looking into your cache to find that webpage again, & it starts to slow windows back down when DSL or CABLE would pull it up much faster than windows could out of the cache. By the time windows searches a second or two for the file, the website would have it puled back up!

Then of course, there is defragmentation. Windows always goes faster after a defrag, hey? But those junk internet files, instead of having to defrag internet trash, it works much faster to get rid of the trash first, then defrag! I know everything you listed about PF files. I have worked with computers for years. I might even know things you never dreamed of knowing about the PF cache. I just know that I do not like having them there, & I want an option to delete them if I want.

You keep saying over & over that is is bad to remove, but the main & mostly ONLY reason I see you posting as a reason not to is that it degrades performance. With high speed machines such as mine, WHO CARES? I mean, a second here or there, well, I rather have a clean machine! Besides, if you just removed malware off someone's machine, do you REALLY want it to keep prefetching all the components of the malware AFTER the malware has already been taken off the machine till windows finally gets chance to remove those?

Me either!

There are just as many arguments against prefetch as there are for, so I see no reason to clean it. If the logic is used that "It speeds up loading applications", then that exact logic can be used against cleaning the internet cache "It speeds up loading web pages!".

If we use this logic as an excuse not to clean, it will never get cleaned!

Peace!

33

If you really want them gone...you know how.

If CCleaner included that...people would think it is a good thing, and that it should be done (simply look at how much people use the Reg cleaner without even knowing what the Registry is).

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If you really want them gone...you know how.

If CCleaner included that...people would think it is a good thing, and that it should be done (simply look at how much people use the Reg cleaner without even knowing what the Registry is).

+1

35

If you really want them gone...you know how.

If CCleaner included that...people would think it is a good thing, and that it should be done (simply look at how much people use the Reg cleaner without even knowing what the Registry is).

Yeah, but the registry cleaner can cause damage if used incorrectly.

There IS no possible damage that can come from clearing the prefetch folder. None. The only possible thing that can happen is windows has to recreate new PF files. So this is not like registry cleaning at all.

How can you possibly even attempt to compare cleaning a temp folder like PF, to registry cleaning that is complex & can go horrendously wrong? I have never, ever, ever heard of a PC getting messed up from clearing the PF folder, including the layout.ini (that windows auto regenerates)

36

Deleting Prefetch files decreases performance - period. There is no possible way it could improve it.

The only PF files worth deleting are the ones from programs you don't use any more, and from (un)installers.

37

Deleting Prefetch files decreases performance - period. There is no possible way it could improve it.

The only PF files worth deleting are the ones from programs you don't use any more, and from (un)installers.

I agree. It could degrade performance. But nothing to brag about. Not that much worse. Windows regenerates them anyway, so it is a very trivial matter. Of course, if you recently removed tons of malware or viruses from a machine, you may not want those to load either.

Or, maybe you do. I am not sure. But I don't. And I like a clean machine.

38

PF files won't load unless you use a program. A malware's PF file would simply be some kilobytes of wasted space, nothing more.