diff --git a/VAX/vax4xx_va.c b/VAX/vax4xx_va.c
index b6e58333..92de2e56 100644
--- a/VAX/vax4xx_va.c
+++ b/VAX/vax4xx_va.c
@@ -1297,6 +1297,7 @@ if (!vid_active)  {
     va_lines = (uint32 *) calloc (VA_XSIZE * VA_YSIZE, sizeof (uint32));
     if (va_lines == NULL) {
         free (va_buf);
+        va_buf = NULL;
         vid_close ();
         return SCPE_MEM;
         }
diff --git a/VAX/vax4xx_vc.c b/VAX/vax4xx_vc.c
index fa4f78f9..4f1d5fc5 100644
--- a/VAX/vax4xx_vc.c
+++ b/VAX/vax4xx_vc.c
@@ -509,6 +509,7 @@ if (!vid_active && !vc_active)  {
     vc_lines = (uint32 *) calloc (VC_XSIZE * VC_YSIZE, sizeof (uint32));
     if (vc_lines == NULL) {
         free (vc_buf);
+        vc_buf = NULL;
         vid_close ();
         return SCPE_MEM;
         }
diff --git a/VAX/vax4xx_ve.c b/VAX/vax4xx_ve.c
index 2a8952c5..61395833 100644
--- a/VAX/vax4xx_ve.c
+++ b/VAX/vax4xx_ve.c
@@ -1460,6 +1460,7 @@ if (!vid_active && !ve_active)  {
     ve_lines = (uint32 *) calloc (VE_XSIZE*VE_YSIZE, sizeof (uint32));
     if (ve_lines == NULL) {
         free (ve_buf);
+        ve_buf = NULL;
         vid_close ();
         return SCPE_MEM;
         }
diff --git a/VAX/vax_va.c b/VAX/vax_va.c
index 19b1d8af..64629fc8 100644
--- a/VAX/vax_va.c
+++ b/VAX/vax_va.c
@@ -1119,6 +1119,7 @@ if (!vid_active)  {
     va_lines = (uint32 *) calloc (VA_XSIZE * VA_YSIZE, sizeof (uint32));
     if (va_lines == NULL) {
         free (va_buf);
+        va_buf = NULL;
         vid_close ();
         return SCPE_MEM;
         }
diff --git a/VAX/vax_vc.c b/VAX/vax_vc.c
index 4c577879..ac603963 100644
--- a/VAX/vax_vc.c
+++ b/VAX/vax_vc.c
@@ -1035,6 +1035,7 @@ if (!vid_active)  {
     vc_lines = (uint32 *) calloc (VC_XSIZE*VC_YSIZE, sizeof (uint32));
     if (vc_lines == NULL) {
         free (vc_buf);
+        vc_buf = NULL;
         vid_close ();
         return SCPE_MEM;
         }
@@ -1043,6 +1044,7 @@ if (!vid_active)  {
         free (vc_lines);
         vc_lines = NULL;
         free (vc_buf);
+        vc_buf = NULL;
         vid_close ();
         return SCPE_MEM;
         }