A file ending in ".1ST" usually is named "READ.1ST" or "README.1ST". These files are normally located in archives such as ZIP or RAR files, or they may be located in an application's main directory.

If the above are true, usually the file is a text file that the application developer(s) believe you should read first before either unpacking the archive or running the application. Such files may contain release notes with important software updates, bug lists, software incompatibilities with various hardware products, etc.

To play it safe, if you wish to open ".1ST" files, use Notepad or another text editor. If the results are gibberish, then the file may have other purposes than those mentioned above.

Windows users: NOTE that unless you have configured your computer with the file extension viewing tweak, it is possible that a filename that looks like it ends with ".1st", especially one attached to an e-mail message, actually has a hidden OTHER extension, meaning that if you double-click the file, it may actually run a computer virus!

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