diff --git a/dlls/ntdll/env.c b/dlls/ntdll/env.c
index 71af0304eae..c1d8a4b3252 100644
--- a/dlls/ntdll/env.c
+++ b/dlls/ntdll/env.c
@@ -538,6 +538,7 @@ BOOL build_command_line( char **argv )
         has_space=0;
         bcount=0;
         a=*arg;
+        if( !*a ) has_space=1;
         while (*a!='\0') {
             if (*a=='\\') {
                 bcount++;
@@ -573,6 +574,7 @@ BOOL build_command_line( char **argv )
         /* Check for quotes and spaces in this argument */
         has_space=has_quote=0;
         a=*arg;
+        if( !*a ) has_space=1;
         while (*a!='\0') {
             if (*a==' ' || *a=='\t') {
                 has_space=1;
diff --git a/programs/wcmd/wcmdmain.c b/programs/wcmd/wcmdmain.c
index daf7ce999a7..8306eef4803 100644
--- a/programs/wcmd/wcmdmain.c
+++ b/programs/wcmd/wcmdmain.c
@@ -97,6 +97,7 @@ int main (int argc, char *argv[])
           has_space=0;
           bcount=0;
           a=*arg;
+          if( !*a ) has_space=1;
           while (*a!='\0') {
               if (*a=='\\') {
                   bcount++;
@@ -131,6 +132,7 @@ int main (int argc, char *argv[])
           /* Check for quotes and spaces in this argument */
           has_space=has_quote=0;
           a=*arg;
+          if( !*a ) has_space=1;
           while (*a!='\0') {
               if (*a==' ' || *a=='\t') {
                   has_space=1;
diff --git a/programs/winevdm/winevdm.c b/programs/winevdm/winevdm.c
index 7075ccb3469..edc23930d8e 100644
--- a/programs/winevdm/winevdm.c
+++ b/programs/winevdm/winevdm.c
@@ -48,6 +48,7 @@ static char *build_command_line( char **argv )
         has_space=0;
         bcount=0;
         a=*arg;
+        if( !*a ) has_space=1;
         while (*a!='\0') {
             if (*a=='\\') {
                 bcount++;
@@ -82,6 +83,7 @@ static char *build_command_line( char **argv )
         /* Check for quotes and spaces in this argument */
         has_space=has_quote=0;
         a=*arg;
+        if( !*a ) has_space=1;
         while (*a!='\0') {
             if (*a==' ' || *a=='\t') {
                 has_space=1;