Open up the Your MT4 indicators folder & physhically take out all the most recent indicators that you have downloaded including EX4 files and just shift them onto your desk top, try restarting MT4 and see if you can isolate the indicator causing the problem, it could be that you have too many indicators loaded onto your platform?? I have had similar issues for no apparent reason happen to me lately after downloading indicators, it is almost like there is a bug or something attached to an indicator perhaps. The most drastic solution i found was to remove the indicators folder to the desk top then start MT4 then i reloaded the indicators folder and all was well, the only thing is that you now have to reset up all your charts, No one else appears to have had this problem as far as i know, i have personally not had any problems with the new STO indicator, it is identical to the earlier STO but with 1 extra set of code for M30 added.

Good Luck cja