Grey bar on left in vim?

In my case, no others but below was the solution.

set signcolumn=no

:set foldcolumn=0

It looks like some plugin creates a sign. Try doing

sign unplace *

To find where this plugin is located, try

vim /path/to/file/that/causes/problem -c 'redir! >/tmp/scriptnames' -c scriptnames -c 'redir END' -c 'qa!'
perl -p -i -e 's/^\s*$//g;s/^\s*\d+:\s//g' /tmp/scriptnames
grep -F -w 'sign define' `cat /tmp/scriptnames`