MS update KB979683 issued yesterday trashes Sandboxie on XP SP3.
As that MS update is critical the answer for anyone running Sandboxie (me :thumb:) is to update to Sandboxie 3.45.07 which Tzuk has just released. Should install over the top without any problems and don't worry about it being a beta, they are as stable as final releases.
Download from here:
http://www.sandboxie.com/index.php?SBIE2306
More info here:
http://www.wilderssecurity.com/showthread.php?t=270143
Thanks, Ian.