I seem to be finding something similar on Windows 10 (64bit)
I have Firefox v56.0 (64) and ccleaner V5.35.6210
When I log off Firefox and the run ccleaner and then log back into Firefox, instead of my home page I get my previous pages returned (or sometimes a Firefox "This is Embarassing" error)
This also happens under ccleaner V5.27 which I just updated but only since Firefox V56
I have Firefox set up so that everything is cleared down when I end that browser session so normally this will just give me my home page when I log in - this is stll working OK UNLESS I run ccleaner in between then I get this prob
(On the ccleaner Firefox options I have all set ON except Site Preferences, Saved Passwords and Compact Databases)
best
Martin
** Edit ** SORRY ! Should have gone to Specsavers - I was so excited to see a thread a;ready open on the topic I hadn't spotted it was for Android only !!
The solution below to untick the "sessions" box for FF56 seems to have wotked - Thanks and again V sorry for misunderstanding