I've used CCleaner for a lot of years, many times daily. The 3.16.1666 64-bit version usually but not always shows a blank window when I try to use the Registry tab. There is no "Scan for Issues", no gridlines, nothing at all; just an empty box.
This is in XP64. If I select Cleaner, all is fine. I return to Registry: nothing.
Reinstallation of CCleaner did no good.
The problem happens usually but not always. I couldn't distinguish a criteria for when it happened.
Eventually I returned to version 3.15.1643 64-bit, and all is working well again.
(1) Turned out it was in 3.15.643 (64-bit) as well.
(2) But I discovered a (very strange) workaround:
—By left-clicking the mouse and dragging the right-hand border of the CCleaner window ANY AMOUNT, the window suddenly "populates" the appropriate gridlines and text inside it.
Notes:
—XP64
—I've used CCleaner for years and years, numerous times daily; never seen this before; likewise CCleaner has lived on the present XP64 for years
—The window, when faulty, is just a totally empty box; nothing inside it at all—BUT ONLY for the Registry function. You can go back and forth to the basic Clean function and that works just fine.
—I'll try for screenshot ASAP. Tonight it is working OK, as though it no longer wants to bedevil me since I discovered the workaround.