I am new to Interactive Brokers but not to trading. I recently opened an account despite the complaints I read about on ET and elsewhere. I trusted them to offer good executions for serious traders. I never lost so much money with bad executions since I am with IB ! At first , last week after I lost 10 grand in one day I felt I was going insane, I was so angry , but then I just became numb , depressed. It happened so quickly and it was so stupid I still can't believe it. It was all because of IB Tws and the popups, yes their POS software, supposedly a state of the art platform for professional traders. Well the idiots who designed this "trader workstation" have no idea what trading is about, they caused me to take my largest loss ever , and in one day ! On Tuesday morning around 7am ET I was short some 30 YG from the week before, I realized the market was going the other way and decided to get out before waiting for a loss. Around 7:30 as I prepared my order , gold started breaking out and I hit the transmit button, that's when I got a pop up window asking me whether I wanted to cancel my attached stop order or the order to cover just sent, wtf ! actually I am not sure what it asked because it went so fast , I was furious. But that was nothing compared to what happened next: in 5 seconds before the order was actually on the exchange, gold jumped 5 points and when all was done I had lost $5,200 ! I couldn't believe my eyes. I decided to follow my rules and keep trading that day, since this wasn't my fault . I would call the IB helpdesk at the end of the day to let them know what happened and see what kind of answer they would give. So on with my trading day , at some point stocks jumped sharply on some Grece related announcement if I recall, S&P made new highs and I made the mistake of going long (15 contracts) , I wasn't sure how far it would go but my risk was limited with that setup, or so I thought, because I didn't count on a repeat of what happened in the morning. I still see it happen before my eyes in slow motion, unbelievable. Shortly after noon, the market stalled and I didn't like what I saw , decided to get out with the very small profit I had. I prepared the order , using "close position", it definitely didn't look good , I hit Transmit. Bam ! S&P collapsed at the exact same time, while I saw the same pop up window that gave me a giant loss in the morning !!! I punched the keyboard first to accept cancelation of my stop, the second strike put a hole in it . ES went down 6 points in one minute . Another $4500 loss. All because of IB ill designed software. If you know a good securities lawyer, please PM.