diff --git a/src/workflows/bidsConcatBetaTmaps.m b/src/workflows/bidsConcatBetaTmaps.m
index 95324f42..b2a6ff46 100644
--- a/src/workflows/bidsConcatBetaTmaps.m
+++ b/src/workflows/bidsConcatBetaTmaps.m
@@ -57,10 +57,13 @@ function bidsConcatBetaTmaps(opt, funcFWHM, deleteIndBeta, deleteIndTmaps)
 
       % beta maps
       outputName = ['4D_beta_', num2str(funcFWHM), '.nii'];
+
+      matlabbatch = [];
       matlabbatch = setBatch3Dto4D(matlabbatch, beta_maps, RT, outputName);
 
       % t-maps
       outputName = ['4D_t_maps_', num2str(funcFWHM), '.nii'];
+
       matlabbatch = setBatch3Dto4D(matlabbatch, t_maps, RT, outputName);
 
       saveAndRunWorkflow(matlabbatch, 'concat_betaImg_tMaps', opt, subID);