Replacer: Free Portable Utility to Replace System Files in Windows

NOTE: The article has been updated with a new software review. The previous software caused problems to some users. You can use this new software without any problem.

Most of the times when we want to customize Windows look, we need to replace existing Windows system files with new files which we download from various websites or we create after modifying default files.

To replace the existing system files, first we need to take ownership of the file using following tutorial:

Add "Take Ownership" Option in File / Folder Context Menu in Windows XP, Vista and 7

Then we need to rename the file to some other name. After that we copy new file to the same folder and restart our system so that Windows can start using new customized file.

If you don't want to to the above mentioned steps, you can use a freeware "Replacer" to replace files automatically.

Just download Replacer, extract the ZIP file and run "Replacer.cmd" file present in the extracted folder. Now you need to drag-n-drop the default system file (which you want to replace) in Replacer's window. After that drag-n-drop the new modified file which will replace the default file. Replacer will ask for confirmation, press "Y" and you have done.

Restart your system and it'll replace the default file with new one upon next reboot.

PS: You can also type the complete file path in Replacer window instead of drag-n-drop the file.


Please note that, before replacing the file it will generate a backup of the original file. The backup is stored in the same folder as the system file, with the extension "backup" (such as "notepad.backup"). If there is an issue with replacing the file, for example, a system file is being used, it will ask if you would like to replace on next Windows boot.

As the file is being replaced, a log is written to "ReplacerUndo.txt" in the Windows folder. If the replacement prevents the system from properly booting, the previous operation can be reversed from the recovery console using BATCH ReplacerUndo.txt command.

You can download it using following link:

Download Link


Also check:

Unlocker: File Unlocking Utility for Windows

LockHunter: Yet Another Free File Unlocker

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Posted in: Software, Windows 7, Windows Vista, Windows XP

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  • didn't work. 'access denied' on win 7 ultimate.

  • VG

    ^^ It works here. Try to run it as Administrator.

  • hey VG, I'm somewhat confuse about to replace user32.dll ; actually i've moded user32.dll for my windows xp sp3. And now want to replace this one but it won't replace, may you guide me to replace..?

  • VG

    ^^ Did you try Replacer? What problem are you facing?

  • nope, going to try, anyway thanks for the comment.

  • hey VG, "Replacer" works thanks for the help.. Along with Plz may you tweet me to replace "user32.dll" file of windows xp setup. Actually "user32.dll" archived in "USER32.DL_" it does open by 7-Zip but it won't not replace OR edit.. I would like to replace my one "user32.dll" into "USER32.DL_"


  • VG

    ^^ Check following:

  • Hello VG, i've a major problem occured with my XP SP3. literally i've replaced some file of my xp sp3 and now whenever i open calculator, i get error message saying.......

    "Illegal System DLL

    The system DLL user32.dll was relocated in
    memory. The application will
    not run properly. The relocation occured because the DLL C;\WINDOWS\system32\SHELL32.dll occupied an address range reserved for Windows system DLLs. The Vendor supplying the DLL
    should be contacted for a new DLL.

    Please elaborate. How to fix this problem.

  • VG

    ^^ It seems your shell32.dll file size is large. Try to restore default shell32.dll file.

  • what maximum size it supports? my shell32.dll is pretty that's why i won't like to restore.. is any other way? Please suggest..

  • VG

    ^^ There is no as such fix size. If you dont want to restore default file, you can replace your new custom BMP, AVI, etc resources in the shell32.dll file with new one which are small in size. It'll help you in reducing shell32.dll file size.

  • brother, OK, i got your talk! Does shell32.dll(which have big size) creates any other problem?? moreover please assert, you have another way to fix this issue.
    Hey VG, one more sheme! Can it be fix if i reinstall xp sp3 with my shell32.dll(which have big size). "cause i don't want change any thing in my shell32.dll" .. my hard work has involved in my "shell32.dll" that's why!

  • VG

    ^^ I think it'll always create same problem even if you slipstream it in setup.

  • Utterly, You was right! its all about size., so can you suggest me to reduce my AVI's size without loosing quality a fraction??

  • my talk mean., how to reduce size of my AVI's even without affecting quality?? rather even better whether it could increase quality!

  • VG

    ^^ No idea. Sorry. You can use other small size AVIs or try to replace existing BMPs with less sized BMPs.

  • certainly, you're winding up! You don't know!! It is almost beyond the bounds of possibility. I know am teasing using my comments but what to do? Literally, I could not find actual resolution on "google" .. that's why! You're computer Expert and i don't think, you didn't know! Do Share your acquaintance!

  • VG

    ^^ Actually I have never tried to make AVIs for progress dialog box so cant help you in this case.

  • OK, brother! It has been fixed now. I think, it supports max 25 mb(approx) .. Nevermind, Yet you helped a lot lot lot. You're simply awesome. All "Gupta" are growing very fast. Thanks is meagre to say so i just only can say.

  • VG

    ^^ Thanks. Glad to help you. :)

  • hey VG, Plz Plz Plz help, i've a major problem occured with Xp installation, i got some errors "3 time with OK prompts" while it was in process of "Registers Components"

    I've uploaded the images. Please check, Error was as follows >>>

    1st time :-

    2nd time :-

    3rd Time :-

    Please help, how to fix this??

  • VG

    ^^ Most probably it seems a corrupt setup disc problem. Did you try nLite or similar software to customize XP setup?

  • hello VG nice to know, You're helping out the people. I've a silly question but what to do, i could not have the solution that's why i'm asking to my favourite VG. Question is : >>
    => how to change icon of
    Folder Options> "Offline File" tab into xp? i just mean, which one dll or exe file shows "Offline File" tab icon.

  • VG

    ^^ I cant tell the exact dll or location as I dont have XP installed in my system but it might present in shell32.dll file.

  • To VG
    I have been using 'Replacer' to replace system files (in my example currently the tray icons)
    But even though I'm using Replacer I still got Windows File Protection Error so I got the WFP patch too but that didn't work after I installed it!!?!!?!!
    I am temporarily reverting icons so the WFP error stops but I may have keep the old icons forever unless you have also encountered a similar problem.

    P.S. Does WFP patcher only work on 1 user??

  • VG

    ^^ It seems WFP service is still running in background. Make sure the patcher successfully disabled the WFP service. Did you try following one?

  • Hey VG, I have installed windows 8 skin pack on my XP. But my windows is not starting up anymore after that.PLEASE HELP.PLEASE.

  • VG

    ^^ You can try to repair Windows XP using setup disc.

  • hey VG im having a problem in changing my shutdown dialog . . . . i tried to delete the original.dll's , but its still coming back . . PLS HELP ME . . :(

  • "Replacer.cmd" does not work in my case trying to replace the system file "logonui.exe" in Win XP. It results always in error message "folders are not allowed"?! What is the reason for that?
    Best wishes from the German capital Berlin

  • yo Vishal
    i have download Metro+Luna visual style for windows 7 and replaced the explorerframe.dll with the new one and when i restarted my pc the explorer frame was in windows 98 style .how can i replace this

  • And i am not able to appy aero theme what should i do reply fast

  • VG

    ^^ It might be a wrong version of the file. Restore the original file.

  • i can't install windows xp or any os in my virtual machine

  • Hi VG,
    im just about going to try theses tutorial, but if i need back my system file (original) how? can u tech me? please

    btw im using win xp and im going to try replacer to system file win 7 by sangopbird (7 mod for xp perfect)

    big thanks

  • VG

    ^^ Just take a backup of the file before replacing it. If you dont like the new file or changes, you can restore original file.

  • how its work with command line?
    can you give me some example to replace imageres.dll with command line

  • help me which file have to replace i cant understand it please tell which file i will replace and how??

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