How do I log all Vim verbose output to a file to diagnose slow startup or plugin issues?

Explanation

Vim's verbosefile option redirects all verbose tracing output to a file on disk instead of printing it to the screen. Combined with verbose=9, every sourced file, option change, and function call is logged, making it invaluable for diagnosing slow startup, mapping conflicts, or unexpected behavior from plugins.

How it works

• verbose=N — sets verbosity level (0 = silent, 1 = tracing basics, 9 = maximum detail)
• verbosefile={path} — writes verbose output to a file instead of the screen
• Setting both before startup captures the entire session from the first script onward

To capture startup in particular, pass them as command-line arguments:

nvim --cmd 'set verbosefile=/tmp/vim.log verbose=9' myfile.txt

For Neovim, you can also use the --startuptime flag as an alternative for profiling startup time specifically.

Example

After running with the flags above, inspect the log:

$ head -30 /tmp/vim.log
sourcing /usr/share/nvim/runtime/filetype.lua
sourcing /home/user/.config/nvim/init.lua
  calling plugin/telescope.lua
  ...

Tips

• Use :set verbose=15 for even more detail including every set invocation
• :messages shows in-session messages but not startup output — verbosefile captures what :messages misses
• After diagnosing, remember to unset: :set verbosefile= verbose=0
• Pair with :profile start /tmp/profile.log to see timing data alongside the trace