How to resolve E303 (Unable to open swap file) on Linux machine?

Question

I get E303 (Unable to open swap file for "{filename}", recovery impossible) when I open a file in vim in my Ubuntu system.

I see that the backupdir and directory environment variables are set correctly in vim -

:se backupdir

backupdir=~/tools/Vim_Files/vim_backup

:se directory

directory=~/tools/Vim_Files/vim_backup

This is the output of ls -l in the shell -
ls -l ~/tools/Vim_Files/

drwxrwxr-x 2 me me 4096 Oct 12 17:02 vim_backup

This is the relevant portion of my .vimrc setting up these variables -

se nobackup writebackup
let s:vim_cstmztn_files_dir='~/tools/Vim_Files/'   
let &directory=s:vim_cstmztn_files_dir.'vim_backup'
let &backupdir=s:vim_cstmztn_files_dir.'vim_backup'

Answer 1

Vim does not interpolate the ~ when using the let & syntax. You must do this manually using expand().

se nobackup writebackup
let s:vim_cstmztn_files_dir=expand('~/tools/Vim_Files/')
let &directory=s:vim_cstmztn_files_dir.'vim_backup'
let &backupdir=s:vim_cstmztn_files_dir.'vim_backup'

Answer 2

I had this issue when there was a space after the path of the swap file directory.

backupdir=~/tools/Vim_Files/vim_backup"     "

Answer 3

Also, make sure that your disk in not full. This error can also occur when there are no more free disk space to create swap file.