Firefox tabs disappearing

I use CCleaner v2.29.1111. Occasionally, when closing Ffox v3.6, then using CCleaner, then opening Ffox again, the earlier tabs are lost except the two first ones (I may have had e.g. six or seven tabs open). All the earlier tabs in question were defined as the Home page in Ffox, and Ffox was asked to save them before closing, as well. I'd be glad of any advice concerning this problem.

Sounds like Firefox is being glitchy with its tab saving, I can't think of anything CCleaner cleans that would cause this.