diff --git a/autoload/ctrlp.vim b/autoload/ctrlp.vim
index 42ff1ed..aea5258 100644
--- a/autoload/ctrlp.vim
+++ b/autoload/ctrlp.vim
@@ -1990,7 +1990,7 @@ endf
 
 fu! s:insertcache(str)
 	let [data, g:ctrlp_newcache, str] = [g:ctrlp_allfiles, 1, a:str]
-	if strlen(str) <= strlen(data[0])
+	if data == [] || strlen(str) <= strlen(data[0])
 		let pos = 0
 	elsei strlen(str) >= strlen(data[-1])
 		let pos = len(data) - 1