hi Helen Borrie
i am not bad in delphi as you mention here :-(
the crash may be cause by

1 - System crash in MS Windows
2 - bug in may app. (no one is completed perfect)
3 - dial up disconected
4 - network abnormal shutdown
.....

if i have 10 user and one of them crahed without commit or rollback
all of 9 user will be in disaster,i must fix this automatically with
rolling back the
transaction belong to disconected database,
is there any way to tell Firebird to do that auto.

it related to firebird not programing language
i try it with IBExpert too.