diff --git a/src/mcx_core.cu b/src/mcx_core.cu
index 78fc821e..bab29f98 100644
--- a/src/mcx_core.cu
+++ b/src/mcx_core.cu
@@ -2821,7 +2821,7 @@ void mcx_run_simulation(Config* cfg, GPUInfo* gpu) {
     /** Updating host simulation configuration \c cfg, only allow the master thread to modify cfg, others are read-only */
     #pragma omp master
     {
-        if (cfg->exportfield == NULL) {
+        if (cfg->exportfield == NULL && cfg->issave2pt) {
             if (cfg->seed == SEED_FROM_FILE && cfg->replaydet == -1) {
                 cfg->exportfield = (float*)calloc(sizeof(float) * dimxyz, gpu[gpuid].maxgate * (1 + (cfg->outputtype == otRF)) * cfg->detnum);
             } else {
diff --git a/src/mcx_utils.c b/src/mcx_utils.c
index 82e6db3a..3fac3a91 100644
--- a/src/mcx_utils.c
+++ b/src/mcx_utils.c
@@ -3698,6 +3698,10 @@ void mcx_validatecfg(Config* cfg, float* detps, int dimdetps[2], int seedbyte) {
         + SAVE_W0(cfg->savedetflag);
     hostdetreclen += cfg->polmedianum ? (4 * SAVE_IQUV(cfg->savedetflag)) : 0; // for polarized photon simulation
 
+    if (!cfg->issave2pt && cfg->issaveref) {
+        cfg->issaveref = 0;
+    }
+
     if (!cfg->issrcfrom0) {
         cfg->srcpos.x--;
         cfg->srcpos.y--;
diff --git a/src/mcxlab.cpp b/src/mcxlab.cpp
index f28963c7..24297b27 100644
--- a/src/mcxlab.cpp
+++ b/src/mcxlab.cpp
@@ -260,7 +260,7 @@ void mexFunction(int nlhs, mxArray* plhs[], int nrhs, const mxArray* prhs[]) {
             }
 
             /** Initialize all buffers necessary to store the output variables */
-            if (nlhs >= 1) {
+            if (nlhs >= 1 && cfg.issave2pt) {
                 int fieldlen = cfg.dim.x * cfg.dim.y * cfg.dim.z * (int)((cfg.tend - cfg.tstart) / cfg.tstep + 0.5) * cfg.srcnum;
 
                 if (cfg.replay.seed != NULL && cfg.replaydet == -1) {
@@ -412,10 +412,11 @@ void mexFunction(int nlhs, mxArray* plhs[], int nrhs, const mxArray* prhs[]) {
 
                 fieldlen = fielddim[0] * fielddim[1] * fielddim[2] * fielddim[3] * fielddim[4] * fielddim[5];
 
-                if (cfg.issaveref) {
+                if (cfg.issaveref && cfg.exportfield) {
                     int highdim = fielddim[3] * fielddim[4] * fielddim[5];
                     int voxellen = cfg.dim.x * cfg.dim.y * cfg.dim.z;
                     float* dref = (float*)malloc(fieldlen * sizeof(float));
+
                     memcpy(dref, cfg.exportfield, fieldlen * sizeof(float));
 
                     for (int voxelid = 0; voxelid < voxellen; voxelid++) {
@@ -438,13 +439,16 @@ void mexFunction(int nlhs, mxArray* plhs[], int nrhs, const mxArray* prhs[]) {
                     free(dref);
                 }
 
-                if (cfg.issave2pt) {
+                if (cfg.issave2pt && cfg.exportfield) {
                     mxSetFieldByNumber(plhs[0], jstruct, 0, mxCreateNumericArray(((fielddim[5] > 1) ? 6 : (4 + (fielddim[4] > 1))), fielddim, mxSINGLE_CLASS, mxREAL));
                     memcpy((float*)mxGetPr(mxGetFieldByNumber(plhs[0], jstruct, 0)), cfg.exportfield,
                            fieldlen * sizeof(float));
                 }
 
-                free(cfg.exportfield);
+                if (cfg.exportfield) {
+                    free(cfg.exportfield);
+                }
+
                 cfg.exportfield = NULL;
 
                 /** also return the run-time info in outut.runtime */