diff --git a/common/lib/share/mccode-r.h.in b/common/lib/share/mccode-r.h.in
index ae3aa200f2..1f0552a07b 100644
--- a/common/lib/share/mccode-r.h.in
+++ b/common/lib/share/mccode-r.h.in
@@ -83,7 +83,7 @@ size_t str_len(const char *s);
 #ifndef _TIMES_H
 #define _TIMES_H
 
-#ifdef _WIN32
+#if defined(WIN32) || defined(_WIN32)
 #include <sys/timeb.h>
 #include <sys/types.h>
 #include <winsock2.h>
@@ -159,7 +159,7 @@ clock_t times (struct tms *__buffer) {
 #  define NEED_STAT_H
 #endif
 
-#ifdef WIN32
+#if defined(WIN32) || defined(_WIN32)
 #  define NEED_STAT_H
 #  define NEED_TYPES_H
 #endif
@@ -173,7 +173,7 @@ clock_t times (struct tms *__buffer) {
 #endif
 
 #ifndef MC_PATHSEP_C
-#  ifdef WIN32
+#if defined(WIN32) || defined(_WIN32)
 #    define MC_PATHSEP_C '\\'
 #    define MC_PATHSEP_S "\\"
 #  else  /* !WIN32 */
@@ -182,12 +182,13 @@ clock_t times (struct tms *__buffer) {
 #  endif /* !WIN32 */
 #endif /* MC_PATHSEP_C */
 
-#ifdef WIN32
+#if defined(WIN32) || defined(_WIN32)
 #if defined _MSC_VER
 #include <direct.h>
 #elif defined __GNUC__
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <unistd.h>
 #endif
 #define mkdir(a,b) mkdir(a)
 #define getpid() _getpid()
diff --git a/mcxtrace-comps/optics/Lens_parab.comp b/mcxtrace-comps/optics/Lens_parab.comp
index cb35b4af45..5f5961e816 100644
--- a/mcxtrace-comps/optics/Lens_parab.comp
+++ b/mcxtrace-comps/optics/Lens_parab.comp
@@ -63,6 +63,9 @@ SHARE
       double tx,ty,tz,tnorm,txn,tyn,tzn;
       double v,w;
 
+      /* Ensure initialisation of t-comps */
+      tx=ty=tz=0;
+
       for(i=0;i<=2;i++){
         result.k[i]=k[i]=a.k[i];
         result.coord[i]=p[i]=a.coord[i];
diff --git a/mcxtrace-comps/optics/Lens_simple.comp b/mcxtrace-comps/optics/Lens_simple.comp
index 3f4834cdff..b5f1cf11d6 100644
--- a/mcxtrace-comps/optics/Lens_simple.comp
+++ b/mcxtrace-comps/optics/Lens_simple.comp
@@ -109,10 +109,12 @@ TRACE
       ABSORB;
   }
 
+  /* Initial calculation of k magnitude */
+  k=sqrt(scalar_prod(kx,ky,kz,kx,ky,kz));
+
   /*change direction towards focal point*/
   if(!f){
     /*Focal length given by lambda and delta*/
-    k=sqrt(scalar_prod(kx,ky,kz,kx,ky,kz));
     e=K2E*k;
     f1=Table_Value(matT,e,1);
 
diff --git a/mcxtrace-comps/sources/Source_flat.comp b/mcxtrace-comps/sources/Source_flat.comp
index f3e26cca7c..14021f4457 100644
--- a/mcxtrace-comps/sources/Source_flat.comp
+++ b/mcxtrace-comps/sources/Source_flat.comp
@@ -158,7 +158,8 @@ TRACE
   rf = sqrt(dx*dx+dy*dy+dist*dist);
   /*pdir contains the unnormalized solid angle weighting */
   p = pmul*pdir/(4*M_PI);
-
+  /* Initial k-norm fallback-value */
+  k=0;
   if (spectrum_file && strlen(spectrum_file) && strcmp(spectrum_file,"NULL")!=0){
     double pp=0;
     //while (pp<=0){