With so many different types of file around these days, it’s important that every file you try to open or execute is correctly identified by Windows. This is obviously achieved by looking at the file extension of .exe or .jpg for example, and when you double click on one of those files, the system knows what it is and what to do with it.
It’s probably happened to you before that you download or receive a file and it has no extension at all or something rather obscure which can’t be correct. In that case, how do you know what the file actually is, could it be a text file, or an MP3, or a zip file? The possibilities are almost endless as to the extension you could give it, and in some cases if you have an idea of what the file is, could get close enough to be able to open the file.
In actual fact, Windows even does this when running a CheckDisk because any corrupted files it recovers are simply named File****.CHK and you have to find the extension yourself to rename it back. Thankfully, we’ve previously covered this topic and you can read more about it in the Ways To Recover CHK Files Created by CHKDSK and SCANDISK article.
If you’re looking for a more generic solution to identifying unrecognized file types, here are 5 tools to help you find them or files which have been given the wrong extension. All programs were tested on Windows 7 32-bit and 64-bit.
1. Locate Opener
Locate Opener installs itself into your right click context menu, and when you run the program executable it simply has an install or remove button to add it into the menu. From there, you right click on an unrecognized or incorrectly labelled file and select LocateOpener from your context menu. Depending on whether the file has no extension at all or one it cannot identify, you will either be asked to look for the extension online at file-extension.net or to scan the file with TrID.
To get the latest file definitions, just download and extract the TrIDDefs.TRD package to Locate Opener’s TrID folder. If the program has found any matches through TrID it will pop up a box with the most likely in terms of percentages, and offer to give the file an extension that best fits. The program also has a command line and several advanced options can be configured through the ini file.
2. Smart File Advisor
This is another program that places itself into your right click context menu, although it does use a more traditional installer unlike Locate Opener’s semi portable tool. Simply right click on the file and select Smart File Advisor from the menu. A box will appear which asks what you want to do next; search its parent website Filefacts.net for the appropriate program or let Windows manage the file by selecting a program via Open with.
The search Filefacts option on its own is not that helpful unless you’re looking for an unknown extension. The most useful function is the tick box in the window that says “send first 20 bytes of the file to help detect file type”. Just about all files can be identified by analyzing the first few bytes of their content so sending these 20 bytes should identify a file with no extension. If you click the link it will show the 20 bytes to be sent in ASCII and HEX format. Click OK to send and a webpage from Filefacts will open to tell you what a missing extension should be or what a wrong extension should be renamed to.
Identify! is a very old utility that dates back to 1999, but still actually works fine, even on Windows 7 x64, and it’s also only a tiny 200K portable executable. There may be newer file formats around since then but the way they’re identified is still exactly the same. The list of around 150 supported types is rather small compared to the 5,000+ in the TrID database, but it covers the most common types. Also Identify! has an added feature built in which is you can easily add your own file formats to its current list or edit what’s already there. Go to Edit -> Library to access the editor.
Run the program to open the window and select File -> “Open and Identify” to locate the file you want to check on. What it’s been identified as will show in the window along with the suggested file extension in brackets. The only thing that doesn’t seem to work in the program is the shell extension option to put an entry in the context menu, but it handles the identification of unknown files without issue. Being small and portable makes it useful for a USB toolkit.
The ExifTool program works in a slightly different way to the other programs here because it’s a command line tool that you can also use from the desktop. Simply extract the executable from the zip file and to identify a file, drag and drop it onto the ExifTool icon. Any extensions the file has will be ignored and its content will be scanned so it doesn’t matter if the file has no extension or simply a wrong extension.
As more knowledgeable users might recognize from its name, Exiftool is designed primarily for viewing and editing the meta information held in most digital images, especially cameras. But it is also capable of recognizing hundreds of different file types from their content. After dropping a file onto the icon a DOS window will open with information about the file and could also include extra information such as image tag details, archive information or executable file descriptions etc. Double click on ExifTool for help, supported types and extra commands that can be used.
5. Analyze It!
Apart from the ability to determine a file type from its content, AnalyzeIt! also has a couple of other functions which could be useful to some. One is getting detailed information about a file extension such as Mime type and classification, the company that created it, its ID and also the characters in Hex and ASCII that identifies it. There’s an even more advanced window of detail in the PE Info tab which can give raw information about executable files. The Content Into tab is the most useful one for identifying unknown files.
The program needs installing and can also place an Analyze It! entry in your right click context menu. The Content info tab displays the file’s attributes, whether it’s a binary or text file, and also the first 16 bytes of its content in Hex and ASCII formats. Experienced users might be able to tell what the file is just from that information alone. Click on the “Analyze file header and content button” and the program will identify the most probable type of file, it will then offer to rename it to the correct extension for you.
Editor’s Note: One of the most popular tools to help identify unknown files is the TrID utility itself. Several tools use the TrID definitions files and library but there is also an old GUI utility if you want to use it. This tool and another which uses the defs file is FiletypeID, both of which have been previously written about in the Recover CHK Files Created by CHKDSK and SCANDISK article. There is also a guide there on how to manually identify unknown files without needing software to do it for you.