I may need to upgrade to Excel 64-bit in order to handle increasingly larger backtest/analysis files (>150MB) that seem to cause 32-bit to constantly crap out (I always get the annoying message "Excel does not have enough resources to complete your request"). The problem is, I also use IB's TwsActiveX file alot for its market scanner and historical data, and on Microsoft's website it says that ActiveX controls are not supported in 64-bit. Is anyone successfully using IB's TwsActiveX.xlsm file with Excel 2010 64-bit? IB tells me there are no compatibility issues, but I wanted to get confirmation from users before I went ahead. Also, are there any other things that I give up if I decide to migrate to 64-bit? The Microsoft website also talks about 64-bit's incompatibility with add-ins, but I don't know of any 3rd party add-ins that I use. Thanks for your help!