What is a .ini file?

About the format

An .ini file is plain-text configuration in the oldest Windows style: [sections] containing key=value lines, with semicolon comments. Windows itself once ran on them (win.ini, system.ini — still present as near-empty compatibility stubs), and countless applications and games still use the format for settings because it's human-readable and trivially editable. Special members of the family: desktop.ini files, which Explorer hides inside folders to customise their icon and display name (a folder suddenly showing a strange name often traces to a stray desktop.ini), and boot.ini from the XP era. Editing an .ini is usually safe and reversible — copy the file first, keep the formatting, and note that programs typically read their .ini at startup, so changes apply on next launch. When a program misbehaves after a settings change, deleting or renaming its .ini often resets it to defaults. The format has no code in it; the worst an edited .ini does is misconfigure its program.

How to open a .ini file

Is a .ini file dangerous?

No — it's configuration text. (desktop.ini quirks are cosmetic, not harmful.)

Related file types