How Windows 98 Managed File Extensions in Explorer

In Microsoft Windows 98, managing file extension visibility was handled through the centralized Folder Options menu inside Windows Explorer. By default, the operating system hid extensions for recognized formats to provide a cleaner interface for novice users, but it offered a straightforward setting within the file manager's preferences that allowed users to reveal full filenames across the desktop and directory windows.

The Default Configuration

When Windows 98 was released, it inherited the file-handling philosophy introduced in Windows 95. The operating system came preconfigured with the "Hide file extensions for known file types" option enabled. Files with registered associations—such as .txt, .doc, .exe, or .bmp—displayed only their base names accompanied by their associated program icons. Only files with unregistered or unknown extensions retained their suffixes in standard views.

Accessing the Visibility Settings

To alter how file extensions were displayed, users had to access the Explorer configuration settings through the following process:

  1. Open Windows Explorer or double-click My Computer.
  2. Click on the View menu located on the top menu bar.
  3. Select Folder Options... from the bottom of the drop-down list.

Opening Folder Options launched a multi-tabbed dialog box consisting of "General," "View," and "File Types."

The controls for visibility were housed entirely under the View tab. This tab presented an "Advanced settings" window containing a tree list of configurable items with checkboxes. Under the Files and Folders category, users located the specific entry labeled Hide file extensions for known file types.

Toggling and Applying Changes

To make all file extensions visible, users unchecked the box next to Hide file extensions for known file types. Clicking Apply immediately updated any open folders in the background, while clicking OK saved the setting and closed the window.

Once disabled, every file displayed its full extension (for example, document.txt instead of just document). This setting applied globally across the entire operating system, including the Windows Desktop, standard Explorer windows, and common Open/Save dialog boxes used by third-party applications.

Security and Usability Implications

Windows 98's method of hiding extensions became a significant topic of discussion regarding system security. During the late 1990s, malicious scripts and executables began exploiting this setting by using double extensions (such as image.jpg.exe). Because Windows 98 hid the .exe portion by default, unsuspecting users saw only image.jpg with a generic icon, making the Folder Options toggle an essential security measure for advanced users and network administrators of the era.