I bought and installed Adobe Photoshop Lightroom 5.7 64-bit on April 8.
I upgraded to Adobe Lightroom 6.0 by purchasing the upgrade and downloading. I now have both versions installed.
When I insert a memory stick, 5.7 automatically starts and asks if I want to import pictures. Is it okay if I uninstall 5.7 from the control panel?
Yes, but you might want to retain a couple of backups of the Lightroom 5 catalog just in case.