diff --git a/NAMESPACE b/NAMESPACE
index 2b05145..f406681 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -92,7 +92,6 @@ importFrom(S4Vectors,"elementMetadata<-")
 importFrom(S4Vectors,DataFrame)
 importFrom(S4Vectors,Rle)
 importFrom(S4Vectors,elementMetadata)
-importFrom(S4Vectors,isEmpty)
 importFrom(S4Vectors,levels)
 importFrom(S4Vectors,subjectHits)
 importFrom(data.table,":=")
diff --git a/R/tabix.functions.R b/R/tabix.functions.R
index 79e00b4..b94a4a2 100644
--- a/R/tabix.functions.R
+++ b/R/tabix.functions.R
@@ -297,7 +297,6 @@ checkTabixHeader <- function(tbxFile,message=NULL) {
 #' @param slotList list of slot items with respective values
 #' @noRd
 #' 
-#' @importFrom S4Vectors isEmpty
 makeTabixHeader <- function(slotList) {
   # first we query each slots and ... 
   tabixHead <- sapply(names(slotList),