I'm running Photoshop CS6 and Lightroom 4 (both 64 bit) on Win 7. I got no errors during installation. Both programs run without issues if run independently and, having installed Nik, and OnOne plugins to PS, I tested them and they seem to work fine as well. However, from within LR4, if I try to edit an image with CS6, I immediately get a Microsoft Runtime error R6034 "an application has made and attempt to load the C runtime library incorrectly". The error does NOT occur if I launch PS independently and then Edit from LR.. only if I try to launch PS from within LR. Thanks for your help.