Robert, i did realize that text disappear mainly if it's Graphite font. and it happens on and off, so no specific way to nail down when it's going to happen.
As for the doors and windows, the files were created in VW8.5 on OS 9.2 and now we are using VW10 on OS10.2.1
doors and windows don't seem to convert very well. the doors' attributes changed from no fill to solid, some needed to be repositioned in the wall because somehow they got shifted and not residing within the wall anymore.
this time, i notice if i update to V2 object on this file, the portion of wall adjacent to the door jams disappear.
or if i insert a new door into the wall, the wall would disappear. what can be the problem? i don't want to have to redraw the entire drawing in VW10. cut and paste doesn't help. Tried that.