I am also having problems with TOPO! under Win7 Pro 64-bit. The program worked for a couple of days, then stopped working for no reason. It starts the launch process, but never gets past the opening banner screen where it says "Please wait while TOPO initalizes...." I have tried installing the various updates for ver. 4, with no change, and tried launching the program under every WIndows COmpatibility Mode possible - again with no change. Interestingly, an old version I had (2.6) works just fine. It's ver 4.x (through 4.502) that's the problem. Anyone found any tricks or hacks that work? Thanks.

I have been unable to get Topo! State Series 4.5 running on Windows 7 Professional 64-bit without some hacking. Expect to have to use their knowledge base and perhaps telephone/mail support. I have been able to get it to run properly on Windows Vista 64-bit without problems. National Geo tech support for this product is rather weak IMHO.

I spoke with National Geographic yesterday regarding compatibility issues & they assured me that not only is version 4.5.0 compatible with Vista but also the new 64 bit Windows 7.