diff --git a/autoload/youcompleteme.vim b/autoload/youcompleteme.vim
index 6ecc4a9a..d9c37a47 100644
--- a/autoload/youcompleteme.vim
+++ b/autoload/youcompleteme.vim
@@ -67,6 +67,7 @@ function! youcompleteme#Enable()
     autocmd InsertEnter * call s:OnInsertEnter()
   augroup END
 
+  call s:SetUpCpoptions()
   call s:SetUpCompleteopt()
   call s:SetUpKeyMappings()
 
@@ -153,6 +154,13 @@ function! s:AllowedToCompleteInCurrentFile()
 endfunction
 
 
+function! s:SetUpCpoptions()
+  " Without this flag in cpoptions, critical YCM mappings do not work. There's
+  " no way to not have this and have YCM working, so force the flag.
+  set cpoptions+=B
+endfunction
+
+
 function! s:SetUpCompleteopt()
   " Some plugins (I'm looking at you, vim-notes) change completeopt by for
   " instance adding 'longest'. This breaks YCM. So we force our settings.