Firefox 64 bits and CCleaner

Dear Friends, if I flag "Compact database" CCleaner 5.27.5976 sends me the message you can see within the attached snapshot.

How can I manage this issue?

Eliminating the flag solves the problem but the question remains: why?

Thank you all!

This does not happens with the previous version of CCleaner, the 5.26.5937 one.

post-78355-0-47144600-1487247460_thumb.jpg

Hello GagliaudO_17,

This will not help you (sorry for that), but I also use Firefox 64-bits and CCleaner (with 'Compact Databases' enabled), but I never saw such a message as you display.