How do I stop Vim from automatically continuing comment markers when I press Enter or open a new line?

Explanation

By default, Vim continues the current comment leader when you press <Enter> in insert mode or open a new line with o/O. This is controlled by the formatoptions setting and its flags. Removing the c, r, and o flags disables this automatic comment continuation.

How it works

The relevant formatoptions flags:

• c — auto-wrap comments at textwidth and insert the comment leader
• r — automatically insert the comment leader when pressing <Enter> in insert mode
• o — automatically insert the comment leader when pressing o or O in normal mode

Removing all three:

:set formatoptions-=cro

To make this permanent for all filetypes, add it to your vimrc. But since ftplugins often re-enable these flags, use an autocmd to ensure it applies after filetype detection:

autocmd FileType * setlocal formatoptions-=cro

Example

With the default formatoptions (includes cro), typing <Enter> after a // comment line in a C file produces:

// first line
// ← cursor here (unwanted)

After set formatoptions-=cro, pressing <Enter> gives a clean empty line:

// first line
← cursor here (clean)

Tips

• Check your current formatoptions with :set formatoptions?
• Use += to add flags and -= to remove them without affecting other flags
• The n flag (formatoptions+=n) makes Vim recognize numbered lists when reflowing with gq
• The j flag removes a comment leader when joining lines with J