Scenario/Problem: You have a file without an extension, and the Finder says it cannot open the file. How do you determine the file type and its associated software?
Solution: Because you have a file without any identifying information, you must use a combination of social analysis and computer sleuthing to determine the type of file and its associated application. Social analysis should be done first, since it is easier and may provide results more quickly.
What is Social Analysis?
With social analysis, you want to determine the file type based on the circumstances in which you came to receive the file. For example, did a coworker email you the file because it relates to a current project? Did you try to download a file for a specific purpose (a disk image, an application, an MP3 file, etc.), but you are only left with an unrecognizable file? Is the file’s creation date relatively recent, or is it several years old? Where is it located on your hard drive? In a system folder, your Downloads folder, or some other location in which you typically work?
Let’s take a look at an example. Suppose you visited a sports team’s web site and looked at its upcoming schedule. The site said that you could download the schedule into iCal or Outlook, so you clicked the link, but nothing happened. A few days later, you notice there is a file in your Downloads folder called “0910homesched.” If you happen to remember that you clicked on a link would add the team’s schedule to iCal, you might believe this is the file. While such a conclusion may be difficult to draw, looking at the name of the file here provides an additional clue. Unfortunately, when you try to open the file, the Finder says it cannot find an application to open the file.
If, however, you believe this file belongs to iCal, there are two ways you can try to open the file:
- First, you can open the application (iCal in this example).
- Next, you attempt to open the file from within the application. This is typically done from the File menu, where you have a choice to Open a file (in iCal, you select Import…).
- Navigate to the Downloads folder and try to select your file. If it works, great! If the file does not open in the application (or if the application will not even let you select the file), try the following method.
Add a file extension to the end of the file name:
- You can add an extension to the file’s name to tell Mac OS X to associate the file with a particular application. How do you know what the proper extension is?
- Visit FileInfo or File-Extensions and search for the relevant application. FileInfo indicates that .ics is the extension for an iCalendar file and is used by Apple’s iCal. In this example, then, you would need to add .ics to the end of “0910homesched” so that the entire file reads “0910homesched.ics.”
- Once you have added the extension, you should be able to go back to the above method and attempt to open the file from within your application.
If neither solution above works, then the most common problems are that the file actually should be opened by a different application or is corrupt (requiring you to get a new copy). You might try repeating the steps above–in order to try a different file extension–if you believe you can draw other reasonable conclusions as to the file’s type.
Previous post: Working with File Extensions in Mac OS X