Thankyou, Im a bit n00b at forcing errors and such, I'll do a bit of reading on it I guess. I'll also have a look at the lot debugger.
thanks for your help
This is pretty much the blind leading the blind, so please take someone else's advice if they offer it.
This is what I do (I think!):
Type Ctrl-Shift-C to bring up the cheat window.
Type 'boolprop testingcheatsenabled true' and hit return.
Select the messed up sim.
Shift-click on the mailbox and choose Force Error.
A dialog pops up with Delete, Reset, or Cancel.
Choose Reset.
If you're not familiar with the extra options in testingcheats, turn it off by
Type Ctrl-Shift-C to bring up the cheat window. (Can't remember if it goes away on its own or not.)
Type 'boolprop testingcheatsenabled false' and hit return.
Type 'exit' to get rid of the window.
P.S. The lot debugger is far more intuitive to use.