Fix: Crash reading some particular old blend files

source/blender/blenkernel/intern/screen.cc

@@ -1188,6 +1188,11 @@ static void direct_link_region(BlendDataReader *reader, ARegion *region, int spa
       if (region->regiontype == RGN_TYPE_WINDOW) {
         BLO_read_data_address(reader, &region->regiondata);
 
+        if (region->regiondata == nullptr) {
+          /* To avoid crashing on some old files. */
+          region->regiondata = MEM_cnew<RegionView3D>("region view3d");
+        }
+
         RegionView3D *rv3d = static_cast<RegionView3D *>(region->regiondata);
 
         BLO_read_data_address(reader, &rv3d->localvd);

source/blender/blenloader/intern/readfile.cc

@@ -3090,6 +3090,9 @@ static void link_global(FileData *fd, BlendFileData *bfd)
       bfd->curscene = bfd->curscreen->scene;
     }
   }
+  if (bfd->curscene == nullptr) {
+    bfd->curscene = static_cast<Scene *>(bfd->main->scenes.first);
+  }
 }
 
 /** \} */