diff --git a/autoload/vimwiki/html.vim b/autoload/vimwiki/html.vim
index 020285b..47c755a 100644
--- a/autoload/vimwiki/html.vim
+++ b/autoload/vimwiki/html.vim
@@ -204,7 +204,7 @@ function! s:subst_func(line, regexp, func, ...) " {{{
 endfunction " }}}
 
 function! s:save_vimwiki_buffer() "{{{
-  if &filetype == 'vimwiki'
+  if &filetype == 'vimwiki' && filewritable(expand('%'))
     silent update
   endif
 endfunction "}}}
diff --git a/ftplugin/vimwiki.vim b/ftplugin/vimwiki.vim
index 9781a67..936ea17 100644
--- a/ftplugin/vimwiki.vim
+++ b/ftplugin/vimwiki.vim
@@ -242,13 +242,15 @@ endfunction "}}}
 
 " COMMANDS {{{
 command! -buffer Vimwiki2HTML
-      \ silent noautocmd w <bar>
+      \ if filewritable(expand('%')) | silent noautocmd w | endif
+      \ <bar>
       \ let res = vimwiki#html#Wiki2HTML(expand(VimwikiGet('path_html')),
       \                             expand('%'))
-      \<bar>
+      \ <bar>
       \ if res != '' | echo 'Vimwiki: HTML conversion is done, output: '.expand(VimwikiGet('path_html')) | endif
 command! -buffer Vimwiki2HTMLBrowse
-      \ silent noautocmd w <bar>
+      \ if filewritable(expand('%')) | silent noautocmd w | endif
+      \ <bar>
       \ call vimwiki#base#system_open_link(vimwiki#html#Wiki2HTML(
       \         expand(VimwikiGet('path_html')),
       \         expand('%')))