• Prefetch folder: what files does it store and why are they needed? What is the Prefetch and Temp folder for in Windows XP? Is it possible to remove virus-infected files from them?

    It is difficult, without being a specialist, to follow the development of the operating room Windows systems. But there are basic concepts that every user should understand. Knowing which folders are responsible for what in Windows will make it easier to navigate the system. An example of files unknown to us is the contents of C:/Windows/Prefetch.

    Purpose of the folder

    Let's answer the question: why is it needed? Prefetch folder? When Windows starts, it analyzes programs that we often use (we open them ourselves or using startup). The system then creates information about these programs, which it stores in special temporary files in the Prefetch folder. Subsequently turning on Windows these files speed up loading of the OS.

    The OS component is responsible for performing this work. If you remove them, no changes will occur. The next time you start it, Windows will again collect current data about programs and place it in the Prefetch folder. However, loading the OS may take a little longer than usual.

    Prefetch was first used in Windows XP. With the advent Windows Vista the folder was supplemented with SuperFetch technologies (responsible for analyzing frequently launched applications) and ReadyBoost (responsible for increasing performance). You can find it in this path: C:/Windows/Prefetch.

    Managing the Prefetcher Service

    You can control the operation of the Prefetcher service in the registry editor:

    This parameter operates with values ​​from 0 to 3, which mean:

    • 0x00000000 - disabling the component;
    • 0x00000001 - acceleration of application loading;
    • 0x00000002 - acceleration Windows startup;
    • 0x00000003 - acceleration of OS and application loading.

    The default value is 3. To disable the service, enter the value 0 and restart the PC.

    Important! The developers made sure that the Prefetch folder did not accumulate files (and gigabytes of disk space), creating a limit of 128 trace files.

    Answers to questions

    Is it possible to delete the Prefetch folder and the data it stores?

    No. This doesn't make sense for three reasons:

    In Windows XP the key /prefetch:1 by default it is added to the file address in the launch icon properties Windows Media Player. What is prefetch? The word prefetch is translated into Russian as “prefetch”.


    The point of this feature is with Windows XP in general. It creates files in the prefetch folder containing information about the paths to these programs on the hard drive.


    On sites in the top Yandex upon request "windows prefetch" You can find some misinformation about this feature in Windows XP. In particular, on the netler and izcity sites, the authors support the myths that to speed up the loading of programs you need to add address lines their shortcuts key /prefetch: 1 , and that to speed up system boot you need to periodically delete all pf format files from the folder prefetch.

    On Windows XP Prefetch folder Usually located at C:\windows\prefetch. It contains Prefetch files with the extension *.pf - these are lists of files to download, so-called hash files. Their names are generated by hashing EXE files after downloading. Every time you launch EXE files, they are hashed and checked to see if there is a corresponding .pf files in the Prefetch folder, and if yes, then these files are downloaded. If no matching prefetch files exist, the system keeps track of which files it uses when launch EXE the program creates this .pf file and saves the paths to these files into it.

    • So first of all, it's not very good idea- clean out the prefetch folder, as some computer sites suggest. The system will simply create all these files again, in any case, unless, of course, you figure out how to disable prefetch.
    • Secondly, Windows automatically deletes prefetch files from this folder if there are more than 128 of them. Therefore, by clearing this folder, you will not only not speed up the loading of programs, but will also temporarily degrade the performance of your computer.

    Next moment...

    Some "specialists" began to add the /prefetch:1 key when starting programs. Many people have noticed that in the automatically created shortcuts for Win Media Player This key is present, and its meaning varies depending on the functions performed by the program. For example, the shortcut to a WMV file that you double-click to watch a video is assigned one prefetch key setting, and the autoplay shortcut for playing or ripping music that appears when you insert an audio CD is assigned another setting.

    Some experts have suggested that the /prefetch: 1 switch enables the process prefetch. And they immediately began adding it to everyone executable file and recommend doing this to others on different sites and forums. And thus this myth was formed. Other experts wrote on their sites that this is complete bullshit, and put forward the theory that this key is specific only to WM Player, having seen links to prefetch files in the Windows driver subsystem.

    In general, neither one nor the other guessed right.

    The operating system looks at the /prefetch:# parameter when it creates a process, and it does so for one single purpose. She adds serial number to hash. For what?

    WMP has a lot different functions. The libraries and code it uses to play WMV are very different from the libraries involved in DVD playback, ripping a CD, listening to a Shoutcast stream, or any of the Windows Media Player features. If there was only one hash for WMP, then prefetch would only work correctly for one of its functions. When reading incorrect data from prefetch file there would be no fatal error - the .pf file would simply be loaded into memory and not be used. However, this would be counterproductive.

    /prefetch:# option different numbers for each function Windows Media Player allows each function to create its own hash file, and thus the prefetching is done correctly. Such prefetch parameters are not unique to WMP. The same is done for any other application.

    /prefetch option: is taken into account when the first thread in a process is created, but is not removed by the CreateProcess function from command line, so any application that doesn't accept unknown command line options will not work with it. That's why so many people noticed that, for example, Kazaa and many other programs produced errors or simply refused to start with windows prefetch. And WMPlayer, of course, knows that the key can be specified in the parameters, and simply silently ignores its existence.

    All the /prefetch:# key does is change the hash number. The operating system loads a program with it in the same way as without it, simply storing the prefetch data in another.pf file.

    Removing unnecessary files

    You know, I never understood the purpose of the Temp folder in Windows. I mean, I don't know why it's needed or what it does. For example, if the installation of a program fails, then certain files are copied to this folder that are subsequently not needed; they can simply be deleted without causing any harm to the system. If there is a malfunction, be sure to check the Temp folder; you will probably find a lot of files in it, taking up precious space on your disk.

    Temp folders are located in two places: C:\Windows\Temp and C:\Documents and Settings\Username\LocalSettings\Temp. By default, the Local Settings folder is hidden, so to see this folder you will have to enable the appropriate option. Now go to these folders and delete all the contents.

    If you haven't opened these folders before, you'll probably be shocked by what's going on in them.

    What is the Prefetch folder

    The Prefetch folder is located in system folder Windows it contains information about frequently opened programs for quick access to them. Used to speed up the loading of the operating system and launch of programs.
    On startup Windows computer monitors the download process. After which the received information is stored on hard drive in the Prefetch folder. The next time you start, this information is used to speed up the loading of the operating system. The same thing happens when you launch any program.

    Clearing the Prefetch folder

    Microsoft decided that the Temp folders were taking up too little of your disk space, so why not create another folder that does the same thing? Thank you very much! No, really, thank you.

    We probably have very few folders that are just eating up the free space. disk space. Now, in addition to the Temp folder, we have a wonderful Prefetch folder. The functions of this folder differ from the functions performed by the Temp folder, however, as in Temp folder, it can hold debris for centuries if you don't remove it manually. Therefore, I advise you to periodically empty this folder (C:\Windows\Prefetch). And don't worry, the system won't suffer from this. Any deleted files, which are required by Windows will be automatically recreated.

    Some users who like to rummage through system directories often come across the Prefetch directory. What is the folder in front of the user in in this case, not everyone knows. Let's try to fill the gaps in knowledge about what this directory is for and what data it contains.

    Prefetch: what is this folder?

    Let's start considering the issue with the submission theoretical material. At start operating system monitors the download process, saving all data about it to speed up subsequent launches in the Prefetch directory. What kind of folder is in front of us?

    Essentially, on the computer’s hard drive, containing current data, parameters and components of the complete system boot cycle and launch of the most frequently used programs.

    To avoid loading all the components from scratch next time, Windows uses the data saved on the hard drive. Some users, however, claim that for each subsequent system startup, the information stored in the Prefetch directory becomes outdated. Therefore, from their point of view, it is necessary to clean out the Prefetch directory from time to time. It’s a little clear what the Prefetch folder is. But not all cleaning enthusiasts know that the data in it is overwritten automatically after each start or launch of the application.

    Let's look at the practical aspects of the issue of deleting its contents. A little later we will talk about how to disable the use of the loading acceleration function if this bothers someone too much.

    Prefetch folder in Windows 7 and higher: is it worth emptying it?

    Removing data from this directory does not make any critical changes to the operation of the system or installed programs will not cause.

    But all those who claim that after removing information from this directory, loading the system and launching applications will become faster are absolutely wrong. Quite the contrary, because the system or program will have to re-launch its own modules, placing them in the operational or computer device, and this takes time. Using data from the Prefetch directory significantly reduces the time spent on these processes. Therefore, by and large, it is undesirable to do cleaning, especially deleting the folder itself.

    It is important to understand here that during subsequent downloads, data about the process will still be saved. So cleaning and removal will turn out to be what is commonly called “Sisyphean labor.”

    Managing the contents of the Prefetch directory

    If someone doesn't need this service, they can get rid of it. To do this you need to enter the editor system registry(regedit command in the “Run” menu, called by the combination Win + R).

    Here you need to select the HKLM branch, and then through the system directory (SYSTEM) and the settings of the current control parameters (CurrentControlSet) go down to the memory inspection section, where the desired PrefetchParameters directory is located. It contains keys of the format 0x0000000z, where “z” can take four possible values:

    • 0 - complete shutdown;
    • 1 - acceleration of program launch only;
    • 2 - optimization of Windows loading only;
    • 3 - activation of the function in full (for both the system and applications).

    The same settings can be made in the editor group policies or in the Computer Administration Tools.

    It remains to add that the directory is located in system partition along the path Windows/Prefetch. What kind of folder is and what it is needed for, I think, is already clear. As a final piece of advice, it's best not to clear the contents of the directory or change the default service settings on the system.

    Hello guys Prefetch is a folder in which difficult data is stored, and those that allow you to work Windows is faster. This data is the result of the work of the service, which in turn analyzes the user’s work at the computer and tries to make sure that next time all the actions he does happen faster.

    Therefore, the Prefetch folder can even be called magical, because thanks to it the computer can work much faster. But exactly how much depends on the free amount of RAM. The more RAM, the better

    Here are the contents of my Prefetch folder:


    If you open its properties, you will see how much space it takes up:

    As you can see, it takes up very little space, so it’s better not to delete it. But what happens if you delete it anyway? Nothing bad will happen, the service will just start working again.

    I deleted it myself to check. Then I rebooted, after which the system worked properly and everything was fine.

    But when I looked in Windows folder, then the Prefetch folder had already been created, well, that is, everything was as I wrote. But when I tried to delete it again, there was a message saying ask for permission from the administrator, well, that’s a joke, I think... But then I clicked repeat and repeat again and that's it, the folder is deleted. So just in case you can’t remove it, here you go special utility, she knows how to delete all stubborn folders. But you, be careful with it, well, with this utility..

    I thought that if I turn it off SuperFetch service, then the folder will not appear after deletion. But no, she showed up anyway. But there was nothing in it except the ReadyBoot folder. That is, the Prefetch folder in some way also relates to the ReadyBoot technology, this is also for speeding up the computer, and a flash drive is used for acceleration... But that’s a completely different story

    Just in case, I’ll tell you how you can disable SuperFetch. So look, launch the dispatcher, go to the Services tab and click this button on it:


    A window will open containing a list of services. Not all of them work, they are just all that are in Windows. Here you need to find SuperFetch and click on it twice.

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