View Full Version : Can't prefetch anything in XP Home

04-03-2004, 02:38 PM
I purchased a new toshiba laptop Satellite A45. 2.8G, 512 Mb, celeron. It has been a real dog even after closing down usless services and startup programs. I tried (bad idea) clearing the prefetch folder expecting it to fill up again. However it will now prefetch the big Nada. Not the boot file or anything at all. I checked the registry to ensure the settings were correct and they were. Enabled and set to option three to prefech all but still nothing. Folder is read only and you can not change that. It just resets to read only. Is this normal?
Any ideas?


04-04-2004, 05:58 AM
It has been a real dog even after closing down usless services and startup programs.Did you disable/manual the 'Task scheduler' service ? Prefetch needs Task scheduler to be in 'automatic'.

04-05-2004, 09:36 PM
Thanks so much for replying. I finally found the answer and yes I had disabled task sched. That still did not set things right all the way. I had to follow on to step 2 of the following procedure and then layout.ini was rebuilt.
Thanx again and I'll watch your posts!


The Prefetch folder should be @
If it's not there, create one.
Highlight C:\WINDOWS | File | New | Folder | Name it: Prefetch | OK.

As has been mentioned, Task Scheduler needs to be set @ Automatic.
Start | Run | Type: services.msc |OK
Scroll down to and double click Task Scheduler | Startup type: Automatic |
Apply | OK |
Close Services.

Start | Run | Type: regedit |OK
Navigate to:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Contro l\Session Manager\Memory
Look for EnablePrefetcher in the right pane, if the value is not 3,
Double click EnablePrefetcher and change the value to 3.
Values are (0 = disabled, 1 = Application launch prefetching, 2 = Boot
prefetching, 3 = Both prefetching). 3 seems to be the preferred option.
Exit regedit
This will take effect on next reboot.
It will take three boots to rebuild the Prefetch file.
If for some reason layout.ini {C:\WINDOWS\Prefetch\layout.ini}does not get
recreated after three boots, try this:
Start | Run | Type: cmd | OK
Paste: rundll32.exe advapi32.dll,ProcessIdleTasks | Enter
At this point, the layout.ini should be rebuilt.
You can force a "boot optimization" by entering the command (in the command
prompt window):
defrag c: -boot | Enter

Open regedit and navigate to:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Dfrg\BootOpt imizeFunction
OptimizeComplete Yes?
Set the LcnStartLocation to zero and the LcnEndLocation to zero
Run the defrag c: -boot again.
This time running "defrag" may take longer.
Again open regedit and navigate to:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Dfrg\BootOpt imizeFunction
OptimizeComplete Yes?
Have the values changed from 0?
By the way Prefetch will purge itself of unused *.pf files.
You don't have to clean it yourself. If you do, *don't* delete the Prefetch
folder, just the contents.

04-06-2004, 03:39 AM
Thanks for posting back broncoapache. Though many recommend cleaning of the prefetch folder atleast once a month, I personally don't see any difference in the performance by doing that. You can delete them, but it's not necessarily desirable. I wouldn't however routinely delete prefetch files as if they were like temporary files.

The Prefetch folder contains records of the load pattern of each program load made. It records files accessed and their timing. Then every three days, when the system has an idle period, a rearrangement of files is made, to bring ones used consecutively together and optimise layout, so that a set of files that are seen to be needed for a program to start up can all be accessed in a single sequence (hence 'prefetched'). This speeds up load times . Older ones are dropped off automatically after seven days, and normally you should leave the folder alone.

04-07-2004, 02:03 PM
Thanks again for replying! I was begining to think no one would. Those are good tips about the prefetch folder and from now on I am going to leave it be. There is so much blather and bad advice on the net sometimes; not all of it about computers.
I think I notice a slight performance increase over the last few days since getting it set right. I'll sure watch your posts from now on as you know of what you speak! Thanks again and peace.