msi: Fix crash while installing Kompas 3D v10 (eterbug #818).

diff --git a/dlls/msi/action.c b/dlls/msi/action.c
index 3799765d816cd28de1eaa409f0d7d29bed713bb3..c90ddf8ab9d22e97d4f11fce8f0101627a33654c 100644 (file)
--- a/dlls/msi/action.c
+++ b/dlls/msi/action.c
@@ -5381,9 +5381,11 @@ static UINT ITERATE_WriteEnvironmentString( MSIRECORD *rec, LPVOID param )
          'S','e','s','s','i','o','n',' ','M','a','n','a','g','e','r','\\',
          'E','n','v','i','r','o','n','m','e','n','t',0};
     static const WCHAR semicolon[] = {';',0};
+    static const WCHAR empty[] = {0};
 
     name = MSI_RecordGetString(rec, 2);
     value = MSI_RecordGetString(rec, 3);
+    if (!value) value = empty;
 
     res = env_set_flags(&name, &value, &flags);
     if (res != ERROR_SUCCESS)