diff --git a/+LLSM/ConvertToKLB.m b/+LLSM/ConvertToKLB.m
index 38691486551e5d85c45bbdeda26beccbf70c8197..229d7a39968b2ab07f9d338e6c5806f7561f8bba 100644
--- a/+LLSM/ConvertToKLB.m
+++ b/+LLSM/ConvertToKLB.m
@@ -38,8 +38,8 @@ function ConvertToKLB(dirIn,dirOut, subfolders, forceDatasetName)
         camMap = unique({parseStruct.cam}.');
         
         frames = unique(vertcat(parseStruct.stack));
-        if ( length(frames) == 1 && ~isempty(parseStruct.iter) )
-            frames = unique(parseStruct.iter);
+        if ( length(frames) == 1 && ~isempty(vertcat(parseStruct.iter)) )
+            frames = unique(vertcat(parseStruct.iter));
         end
         
         tiffName = LLSM.MatchFilename(parseStruct, camMap(1), frames(1), chanMap(1));