# identifying an unknown file type **URL:** \ **Category:** Factual Questions\ **Created:** [March 25, 2005, 1:25pm UTC](https://boards.straightdope.com/t/identifying-an-unknown-file-type/296191 "2005-03-25T13:25:24Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![pope\_hentai](https://avatars.discourse-cdn.com/v4/letter/p/ee59a6/32.png) [@pope\_hentai](https://boards.straightdope.com/u/pope_hentai)\ **Post date:** [March 25, 2005, 1:25pm UTC](https://boards.straightdope.com/t/identifying-an-unknown-file-type/296191/1 "2005-03-25T13:25:24Z")
ok so i’ve downloaded this file… but it has no extension for some unknown reason. how do i identify exactly what this extension should be? ---
**Author:** ![critter42](https://avatars.discourse-cdn.com/v4/letter/c/7ba0ec/32.png) [@critter42](https://boards.straightdope.com/u/critter42)\ **Post date:** [March 25, 2005, 2:00pm UTC](https://boards.straightdope.com/t/identifying-an-unknown-file-type/296191/2 "2005-03-25T14:00:34Z")
If it’s not an illegal file (ie, warez/porn/etc), are you at liberty to share the URL with us? without knowing more, we can’t tell you either. Now, how would _I_ identify an unknown file? First I’d look at the website I was downloading it from - is it a picture, a movie, a sound file, a program? Does it mentioned if it’s a compressed file? Once you know what kind of file it is, that will narrow down the extension to use. If you can just tell us what kind of file it’s supposed to be, we may be able to point you to an appropriate tool that will be able to give you the info. There is also the possibility that this file may be for a different operating system than Windows Additionally, with some files, if you open it up with Wordpad or Notepad, you might get lucky and there may be some plain-English readable words and phrases at the very beginning or the very end that will indicate what kind of file it is. ---
**Author:** ![daffyduck](https://avatars.discourse-cdn.com/v4/letter/d/ec9cab/32.png) [@daffyduck](https://boards.straightdope.com/u/daffyduck)\ **Post date:** [March 25, 2005, 3:33pm UTC](https://boards.straightdope.com/t/identifying-an-unknown-file-type/296191/3 "2005-03-25T15:33:18Z")
I can’t imagine that you would go to the trouble of downloading a file without having some idea of what it is supposed to be. Just try giving it the file extension you think it should have and then see if it opens. If it is a picture, try all the different picture formats and likewise for a movie. ---
**Author:** ![pope\_hentai](https://avatars.discourse-cdn.com/v4/letter/p/ee59a6/32.png) [@pope\_hentai](https://boards.straightdope.com/u/pope_hentai)\ **Post date:** [March 25, 2005, 4:16pm UTC](https://boards.straightdope.com/t/identifying-an-unknown-file-type/296191/4 "2005-03-25T16:16:45Z")
its supposed to be a compressed file i would try openeing it in notepad/wordpad but its about 600 megs ---
**Author:** ![bouv](https://avatars.discourse-cdn.com/v4/letter/b/bc8723/32.png) [@bouv](https://boards.straightdope.com/u/bouv)\ **Post date:** [March 25, 2005, 4:25pm UTC](https://boards.straightdope.com/t/identifying-an-unknown-file-type/296191/5 "2005-03-25T16:25:40Z")
Well, if it’s a compressed file, (lke a zip or rar) then get WinRAR, or some other unpacking utility other than Winzip, and uncompress it. Are you sure there’s no extension? Do you have the ‘hide extension of known file types’ option turned on or off in the folder view options? ---
**Author:** ![ParentalAdvisory](https://avatars.discourse-cdn.com/v4/letter/p/53a042/32.png) [@ParentalAdvisory](https://boards.straightdope.com/u/ParentalAdvisory)\ **Post date:** [March 25, 2005, 4:57pm UTC](https://boards.straightdope.com/t/identifying-an-unknown-file-type/296191/6 "2005-03-25T16:57:44Z")
> [@pope\_hentai](#): > > its supposed to be a compressed file i would try openeing it in notepad/wordpad but its about 600 megs Hmm, and unknown compressed 600 meg file… does it have a .BIN, .ISO, or .CUE for an extension? ---
**Author:** ![pope\_hentai](https://avatars.discourse-cdn.com/v4/letter/p/ee59a6/32.png) [@pope\_hentai](https://boards.straightdope.com/u/pope_hentai)\ **Post date:** [March 25, 2005, 5:02pm UTC](https://boards.straightdope.com/t/identifying-an-unknown-file-type/296191/7 "2005-03-25T17:02:45Z")
found out what it was… an avi file… and now i’m very dissapointed. thank you for the help. ---
**Author:** ![vetbridge](https://avatars.discourse-cdn.com/v4/letter/v/b5e925/32.png) [@vetbridge](https://boards.straightdope.com/u/vetbridge)\ **Post date:** [March 25, 2005, 5:05pm UTC](https://boards.straightdope.com/t/identifying-an-unknown-file-type/296191/8 "2005-03-25T17:05:51Z")
> [@bouv](#): > > Well, if it’s a compressed file, (lke a zip or rar) then get WinRAR, or some other unpacking utility other than Winzip, and uncompress it. Why not WinZip? ---
**Author:** ![bouv](https://avatars.discourse-cdn.com/v4/letter/b/bc8723/32.png) [@bouv](https://boards.straightdope.com/u/bouv)\ **Post date:** [March 25, 2005, 6:18pm UTC](https://boards.straightdope.com/t/identifying-an-unknown-file-type/296191/9 "2005-03-25T18:18:48Z")
> [@vetbridge](#): > > Why not WinZip? Well, AFAIK, WinZip doesn’t do RAR archives, or at least didn’t last time I had it (but then that was a few years ago.) Plus, it’s only a 30 day trail when you download it, and every time you use it after 30 days you get an annoying message telling you to stop using it (yet it still lets you…) ---
**Author:** ![vetbridge](https://avatars.discourse-cdn.com/v4/letter/v/b5e925/32.png) [@vetbridge](https://boards.straightdope.com/u/vetbridge)\ **Post date:** [March 25, 2005, 6:26pm UTC](https://boards.straightdope.com/t/identifying-an-unknown-file-type/296191/10 "2005-03-25T18:26:52Z")
OK, thanks.