diff --git a/autoload/sy.vim b/autoload/sy.vim
index 41bbf4a..53b9e4a 100644
--- a/autoload/sy.vim
+++ b/autoload/sy.vim
@@ -28,18 +28,19 @@ function! sy#start(path) abort
   " new buffer.. add to list of registered files
   if !has_key(g:sy, a:path)
     if get(g:, 'signify_disable_by_default')
+      " register file as inactive
       let g:sy[a:path] = { 'active': 0, 'type': 'unknown', 'hunks': [], 'id_top': g:id_top, 'stats': [-1, -1, -1] }
       return
     endif
 
     let [ diff, type ] = sy#repo#detect(a:path)
-    if empty(diff)
-      " register file as active with either no changes or no found VCS
+    if type == 'unknown'
+      " register file as active with no found VCS
       let g:sy[a:path] = { 'active': 1, 'type': 'unknown', 'hunks': [], 'id_top': g:id_top, 'stats': [0, 0, 0] }
       return
     endif
 
-    " register file as active and containing changes
+    " register file as active with found VCS
     let g:sy[a:path] = { 'active': 1, 'type': type, 'hunks': [], 'id_top': g:id_top, 'stats': [0, 0, 0] }
 
     let dir = fnamemodify(a:path, ':h')
@@ -47,22 +48,27 @@ function! sy#start(path) abort
       let g:sy_cache[dir] = type
     endif
 
+    if empty(diff)
+      " no changes found
+      return
+    endif
+
   " inactive buffer.. bail out
   elseif !g:sy[a:path].active
     return
 
-  " retry detecting changes or VCS
+  " retry detecting VCS
   elseif g:sy[a:path].type == 'unknown'
     let [ diff, type ] = sy#repo#detect(a:path)
-    if empty(diff)
-      " no changes or VCS found
+    if type == 'unknown'
+      " no VCS found
       return
     endif
     let g:sy[a:path].type = type
 
   " update signs
   else
-    let diff = sy#repo#get_diff_{g:sy[a:path].type}(a:path)
+    let [ _, diff ] = sy#repo#get_diff_{g:sy[a:path].type}(a:path)
     if empty(diff)
       call sy#sign#remove_all(a:path)
       return
diff --git a/autoload/sy/repo.vim b/autoload/sy/repo.vim
index 26c3471..227e246 100644
--- a/autoload/sy/repo.vim
+++ b/autoload/sy/repo.vim
@@ -53,20 +53,21 @@ function! sy#repo#detect(path) abort
   endif
 
   for type in s:vcs_list
-    let diff = sy#repo#get_diff_{type}(a:path)
-    if !empty(diff)
+    let [istype, diff] = sy#repo#get_diff_{type}(a:path)
+    if istype
       return [ diff, type ]
     endif
   endfor
 
-  return [ '', '' ]
+  return [ '', 'unknown' ]
 endfunction
 
 " Function: #get_diff_git {{{1
 function! sy#repo#get_diff_git(path) abort
   let diffoptions = has_key(s:diffoptions, 'git') ? s:diffoptions.git : ''
   let diff = system('cd '. sy#util#escape(fnamemodify(a:path, ':h')) .' && git diff --no-color --no-ext-diff -U0 '. diffoptions .' -- '. sy#util#escape(a:path))
-  return v:shell_error ? '' : diff
+
+  return v:shell_error ? [0, ''] : [1, diff]
 endfunction
 
 " Function: #get_stat_git {{{1
@@ -104,63 +105,66 @@ endfunction
 function! sy#repo#get_diff_hg(path) abort
   let diffoptions = has_key(s:diffoptions, 'hg') ? s:diffoptions.hg : ''
   let diff = system('hg diff --nodates -U0 '. diffoptions .' -- '. sy#util#escape(a:path))
-  return v:shell_error ? '' : diff
+
+  return v:shell_error ? [0, ''] : [1, diff]
 endfunction
 
 " Function: #get_diff_svn {{{1
 function! sy#repo#get_diff_svn(path) abort
   let diffoptions = has_key(s:diffoptions, 'svn') ? s:diffoptions.svn : ''
   let diff = system('svn diff --diff-cmd '. s:difftool .' -x -U0 '. diffoptions .' -- '. sy#util#escape(a:path))
-  return v:shell_error ? '' : diff
+
+  return v:shell_error ? [0, ''] : [1, diff]
 endfunction
 
 " Function: #get_diff_bzr {{{1
 function! sy#repo#get_diff_bzr(path) abort
   let diffoptions = has_key(s:diffoptions, 'bzr') ? s:diffoptions.bzr : ''
   let diff = system('bzr diff --using '. s:difftool .' --diff-options=-U0 '. diffoptions .' -- '. sy#util#escape(a:path))
-  return ((v:shell_error == 0) || (v:shell_error == 1) || (v:shell_error == 2)) ? diff : ''
+
+  return (v:shell_error =~ '[012]') ? [1, diff] : [0, '']
 endfunction
 
 " Function: #get_diff_darcs {{{1
 function! sy#repo#get_diff_darcs(path) abort
   let diffoptions = has_key(s:diffoptions, 'darcs') ? s:diffoptions.darcs : ''
   let diff = system('cd '. sy#util#escape(fnamemodify(a:path, ':h')) .' && darcs diff --no-pause-for-gui --diff-command="'. s:difftool .' -U0 %1 %2 '. diffoptions .'" -- '. sy#util#escape(a:path))
-  return v:shell_error ? '' : diff
+  return v:shell_error ? [0, ''] : [1, diff]
 endfunction
 
 " Function: #get_diff_fossil {{{1
 function! sy#repo#get_diff_fossil(path) abort
   let diffoptions = has_key(s:diffoptions, 'fossil') ? s:diffoptions.fossil : ''
   let diff = system('cd '. sy#util#escape(fnamemodify(a:path, ':h')) .' && fossil set diff-command "'. s:difftool .' -U 0" && fossil diff --unified -c 0 '. diffoptions .' -- '. sy#util#escape(a:path))
-  return v:shell_error ? '' : diff
+  return v:shell_error ? [0, ''] : [1, diff]
 endfunction
 
 " Function: #get_diff_cvs {{{1
 function! sy#repo#get_diff_cvs(path) abort
   let diffoptions = has_key(s:diffoptions, 'cvs') ? s:diffoptions.cvs : ''
   let diff = system('cd '. sy#util#escape(fnamemodify(a:path, ':h')) .' && cvs diff -U0 '. diffoptions .' -- '. sy#util#escape(fnamemodify(a:path, ':t')))
-  return ((v:shell_error == 1) && (diff =~ '+++')) ? diff : ''
+  return ((v:shell_error == 1) && (diff =~ '+++')) ? [1, diff] : [0, '']
 endfunction
 
 " Function: #get_diff_rcs {{{1
 function! sy#repo#get_diff_rcs(path) abort
   let diffoptions = has_key(s:diffoptions, 'rcs') ? s:diffoptions.rcs : ''
   let diff = system('rcsdiff -U0 '. diffoptions .' '. sy#util#escape(a:path) .' 2>/dev/null')
-  return v:shell_error ? '' : diff
+  return v:shell_error ? [0, ''] : [1, diff]
 endfunction
 
 " Function: #get_diff_accurev {{{1
 function! sy#repo#get_diff_accurev(path) abort
   let diffoptions = has_key(s:diffoptions, 'accurev') ? s:diffoptions.accurev : ''
   let diff = system('cd '. sy#util#escape(fnamemodify(a:path, ':h')) .' && accurev diff '. sy#util#escape(fnamemodify(a:path, ':t')) . ' -- -U0 '. diffoptions)
-  return (v:shell_error != 1) ? '' : diff
+  return (v:shell_error != 1) ? [0, ''] : [1, diff]
 endfunction
 
 " Function: #get_diff_perforce {{{1
 function! sy#repo#get_diff_perforce(path) abort
   let diffoptions = has_key(s:diffoptions, 'perforce') ? s:diffoptions.perforce : ''
   let diff = system('env P4DIFF=diff p4 diff -dU0 '. diffoptions .' -- '. sy#util#escape(a:path))
-  return v:shell_error ? '' : diff
+  return v:shell_error ? [0, ''] : [1, diff]
 endfunction
 
 " Function: #process_diff {{{1