Windows on File rename gives warning – "If you change a filename extension,the file may become unusable"


Recently one of our readers Miku reported a problem, whenever he tries to rename any file, he gets a warning message saying:

If you change a filename extension,the file may become unusable. Are you sure you want to change it?”

Warning can be seen in snapshot below.

Rename warning

This simply happens because when user tries to rename the file when the extensions of file are shown, he/she forgets to give the extension and gives only new filename. This makes the file to become un-recognized by windows (or any operating system).

Let’s see how can we solve it.


The solution to this trouble is also very simple, lets see how we can fix it.

Method 1 :

The simplest way to fix such issue is to make the file extensions hidden. When you do that, windows will take care that the file extensions are not changed while renaming the file. To make the file extensions hidden, follow the below steps:

1. Open My Computer, go to Tools > Folder Options > View

2. Check the option “Hide extensions for know file types”.

3. Click Apply and OK.As seen in image below.

Hide extension

Method 2 :

Always provide the extension to the file explicitly as it was previously. For example if you want to rename a zip file from old name file1 to new name file2, make sure you rename the file from to This means you have to type the extension manually.

We hope this helps to understand why the warning got flashed


  1. I have pleased on the solution. It has cleared it all thank you very much.
    from Ethiopia

  2. >>This simply happens because when user tries to rename the file when the extensions of file are shown, he/she forgets to give the extension and gives only new filename.

    It’s rather narrow minded reason.

    I need tho change extensions somteimes, not just to rename a file forgetting an extension. For example, to change *.ra to *.rar

    So your solution is just for several users who didn’t get lucky to get a system with DEFAULT setting of not showing extensions for known formats.


  3. Great help! Thanks! Was losing valued graphics and picture files. A few clicks fixed things. Method one worked FAST.

  4. GEEZ that was getting so annoying. Thank you for solving my problem.

    …I’m pretty sure I was living without renaming anything for at least 7 months.

  5. Thanks for solving my file extension problem
    I even went to MS site and could not provide the answer
    thanks again

  6. thank u so much for solving the problem i faced and clearing all my frustration. 😉

  7. that’s no solution for me.
    1. i always want to see which extensions my files have
    2. as a coder i often create simple .txt files by a right click and rename it after my work to e.g. php, bat, cs, …

    so i think there has to be a better way to disable the warning

  8. I have this problem also.

    Whenever I rename my files I get these annoying error messages telling me I’m changing the extension.

    I KNOW I’m changing the extension, it’s on purpose.

    How do I get rid of these annoying error messages from appearing every time I try and change the extension?

  9. simple solution…..nonetheless effective.
    this kind of small solution can be clarified by these kind of forums is very good.

  10. The workaround I use is a 3rd party tool which can automatically click a button on specified dialog – in this case the ‘Yes’ buttom for this silly warning window.

  11. you are doing a great job in fixing the problems.thanks a lot.

  12. I have pleased on the solution. It has cleared it all thank you very much

    your solutions solved the problem in my note book also. thanks a lot.

  13. Thanks a million!I almost went to the extent of installing new OS for my computer.

  14. thanks!!!i thought it was a virus.maybe someone accidentaly unchecked the box.thanks again!

  15. Thanks for solving my problem,ur great@@@@@@Thanks a lot…………………………….

  16. thanks man for solving my problem it really helps a lot.

  17. Marry me !!!!!!!

    I have BIG IMPORTANT lecture tomorrow and this thing was driving me crazy!

    This is not help, you are a lifesaver ;******

  18. Thankuu Very very very very…..Much.
    This Is Very very very very……Guddddd Site.
    Thankuuuuuu Againnnn To solve My Problammmm..

  19. Sorry this hasn’t worked for me. I have done exactly as you stated but not working?

  20. really i very very thank for u solve my problem……..

  21. Thank you. This worked just as you said. Do you know why it happens though? After performing this fix I restored defaults to discover several settings on my computer have been changed.
    Could it be a bug?

  22. Thank you. really solve my problem this worked is really just as said.
    i lost maney my photo problem of Rename . thank.

  23. thank you for solving my problem
    I don’t know what is file extension and how to provide it

  24. thankx man great help…keep going add some more relevent trouble shooters…..Nurul jakarta

  25. i just wana say thanks to u 4 this great soln ……nearly searching 15 website finally i have found this simple and lucid answer …..

  26. Thank you very much , really that solved my problem . I was thinking that infection of virus . again thank you

  27. I agree with stretch and Vaer…this is not helpful if you actually need to 1) see your file extensions and 2) need to change them often

    Has anyone found a solution to keep this message from popping up where you are still able to see your file extensions and when you need to change them for legitimate reasons and are very aware that if the file extension is incorrect the file will be unusable?

  28. Dear Sir Thank You very much to make my problem solved, previously i thought my window got currupted and i re-install the entire window xp. Thanks again for solving this problem so very kind of you.

    Best Regards


    YOU GREAT MEN…………………………………………………………………………………………………………………………………………………………………..VERY VERY THANK YOU

  30. thank u soooooooooooooooooooooooooooooooooooooooooooooooooooooo much friend

  31. THANK YOU VERY VERY VERY MUCH…………………………………………………

  32. damn!!… tnx so much dude, i was so stressed of this isue, i think it was coz the auto setings of other viewer on my machine, tnx a lot again ———-SOLVED———

  33. thanks for solving my problem i am suffering from a lot of problem

  34. Thank you very much for providing good solution. I was in trouble from the several days I was thiking to contact software Eng. But you did solve my problem within a minuts. Thanks again.

  35. this is not a “fix”, it is for people who know nothing about computers. For those of us who are programmers and create their own file extensions, and need them always on, and need to change file extensions with F2 hundreds of times daily, can you PLEASE provide a way to turn off this annoying confirmation dialog box in windows xp?


  37. Thanks a lot sir for providing this information, My problem is resolved.May God help you.

  38. this was very useful information to me to solve the problems.
    thanks thanks a lot 🙂

  39. Thank you very very much for this information. I was suffered from this problem for long time. Wow! very fruitful information. Thanks once again.

  40. ohhhhhhhh my god.thnx v.much fr the valuable infrmation.thnx alooooooooooooootttttt

  41. thanks
    I solve my problem very easy
    thanks for use pictures to explain

  42. tahnks sir its very valuable information u share with us thanks thanks……………………………..

  43. Dear Sir Thank you very much , really that solved my problem . again thank you Sir

  44. This solution does not work. Clearly, all the people replying “yay, this worked for me” are either shills, or just plain don’t understand what is going on.

    If I want to change a file extension from .xls to .xlst (or whatever) windows pops up this window in an attempt to save me from myself.

    I am an experienced programmer, and I know what I am doing. I don’t need to be saved from myself (I guess 99% of the rest of the world does need that protection.

    There is NO WAY to disable this warning. Turning off seeing file extensions is a fix for a symptom, not the problem.

    Clearly, the author of this post falls into the 99% because he doesn’t understand the issue. He is supplying an answer for a problem that was not asked.

    I really wish idiots who didn’t know what they are doing would stay off help sites.


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