I had 1.5 on my system. But I was only using it occasionally. Updated to 1.61 when I saw it used MFT instead of indexing. I don't know why but when minimized to tray, Shift Backspace seems to work as hotkey in addition to whatever is selected in options.
This is a really nice little utility.
edit: seems to be not smooth on shutdown or logoff when Minimize To Tray is enabled. Also may interfere with MagicJack when "autocheck new drives" is enabled. I would really like it if those rough spots were sanded down. Nice simple interface.
edit2: I noticed I added an entry to my general-purpose tray hotkey script to open UltraSearch in response to Shift Backspace. The weird behavior may be do to my script and not an UltraSearch bug. If I find out more I'll edit here. Don't mean to blame the software. With these hotkey things it's easy to forget when you add one.