A daily updated filename extension database!

999 file extension

The table below provides useful information about the .999 file extension. It answers questions such as:

  • What is the .999 file?
  • What program do I need to open a .999 file?
  • How can the .999 file be opened, edited or printed?
  • How can I convert .999 files to another format?

Table of Contents

We hope you find this page helpful and a valuable resource!

1 extension(s) and 0 alias(es) found in database

✅ Multipass Security Data

Multipass Security Data .999 file icon
999 file is a Multipass Security Data. Multipass is a utility that will help you to remember the multitude of passwords that are rushed on any user of Internet.
999 format description not yet available
Category: Data files
Application: Multipass
Mime-type: application/octet-stream
Magic number: -
Magic string: -
Sample: -
999 aliases:
999 related links:
999 related extensions:

Other types of files may also use the .999 file extension.

🚫 The .999 file extension is often given incorrectly!

According to the searches on our site, these misspellings were the most common in the past year:


Is it possible that the filename extension is misspelled?

We found the following similar file extensions in our database:

MicroStation Modification Project Resource File

🔴 Can't open a .999 file?

When you double-click a file to open it, Windows examines the filename extension. If Windows recognizes the filename extension, it opens the file in the program that is associated with that filename extension. When Windows does not recognize a filename extension, you receive the following message:

Windows cannot open this file:


To open this file, Windows needs to know what program you want to use to open it...

If you don't know how to set the .999 file association, check the FAQ.

🔴 Can I change the extension of files?

Changing the filename extension of a file is not a good idea. When you change a file's extension, you change the way programs on your computer read the file. The problem is, changing the file extension does not change the file format.

If you have helpful information about the .999 file extension, write to us!

Browser: Abbreviation Application Archive Audio Configuration Data Development Disk Image Document Ebook Font Game Data GIS Graphic Malware Multimedia Other Project Scam Unknown Video
This page is available in the following languages: Český Deutsch English Español Suomi Français Magyar Italiano 日本語 Nederlands Norsk Português Român Русский Svensk 中文