Gents, I have been trying to track down this anomaly for about 4 months to no avail. I am currently running TWS Build 875.3 with Java 1.6.0_02 on XP Pro. Everything starts normally, and I have the 5 level DOM. If I execute market orders off TWS or custom market buy/sell buttons on Booktrader, everything is OK. Problem is if I execute limit orders, or bracket spreads off of Booktrader, or thru the API via BracketTrader, the 5 level DOM in IB Booktrader corrupts, and eventually ends with no data in the slots. The DOM data is lost in IB Booktrader, Bracket Trader and an Excel DOM graphing function, all my running applications. Restarting Booktrader has no effect. Only closing TWS and restarting clears the problem. Ctrl-R, relogon has no effect. I just uninstalled all Java loads and updates today, and freshly installed Java 1.6v2 to no avail. Any suggestions are appreciated. I am pretty much at my wits end on causes. I am running QuoteTracker as my graphing program. Any thoughts or suggestions sincerely appreciated.