Hi,
Could you clarify why you think Disk Cleaner is erasing your email passwords?
Disk Cleaner erases the following:
Junk files: Unnecessary files (such as driver packages, temporary files, and log files) that occupy a lot of space and slow down your system.
Downloads & Recycle Bin (unselected by default): The contents of your Downloads folder and Recycle Bin. These items will not be removed from your PC unless you manually select this category.
Broken registry keys: Links in your system registry that may be outdated or broken.
Broken shortcuts: Invalid shortcuts leading to non-existent files or applications.