I am starting to have the same problem now since I upgraded to build 600
The indicator only works everytime you recompile it again. There are no errors.
As soon as you close MT4 and reopen it, the indicator doesn;t work/update, it freezes somehow.
i don't speak english very well but i will try to do my best to help you. it's my first post in this very helping forum ^^
you have to do an error check to every call to MarketInfo(*******.
and if there is any error, hard code the value required (like spread = bid - ask, point ....ect)
i found that many bugs can occures, especially with this function in different terminal/history/tester conditions without any error reported by terminal, those are logic error, and it is frustrating to detect them without systematically tracking them after the call to the function MarketInfo().
generally speaking, bugs occurs only when they are not expected / handled: always do checks for logic errors (Value != expected values, with error reporting in log && a global variable Errors increment to verify if there is any) for all function calls, function core (before returning values) and calculated variables values, as many checks as possible.