I have just recently defenestrated Windows 10 and installed Linux Mint 17.3 Cinnamon.
Everything went fine for the first week and I was just beginning to have fun when Mint started misbehaving.

All my Thunderbird settings disappeared and I was back to square one. All the folders that I created in my inbox are gone along with the emails saved in them.

Google disappeared as my homepage and I was presented with a whole batch of Amazon adds.

A lot of what appears to be system folders, appeared when I clicked on my files menu.

All my other settings were changed. Some back to default, others to unfamiliar settings. Some files won't open at all.

I'm not ruling out pilot error although I do not believe that is the problem.

Please do not tell me that I have to start from scratch. It has been a mission to get where I am.

Rusty

Show us these system folders via screenshot or just name 3 of them here.

Open your terminal and issue:
and upate this post with the result.

Thank you.

Thanks for your response

When I enter ls -ld ~/.mozilla in the command line in Terminal, this is what I get.

rusty@rusty-300E4A-300E5A-300E7A-3430EA-3530EA ~ $ ls -ld ~/.mozilla
drwx------ 4 rusty rusty 4096 Feb 8 08:23 /home/rusty/.mozilla


When I enter this is what I get.

rusty@rusty-300E4A-300E5A-300E7A-3430EA-3530EA ~ $ [CODE]ls: command not found
rusty@rusty-300E4A-300E5A-300E7A-3430EA-3530EA ~ $

Thanks for your response

When I enter ls -ld ~/.mozilla in the command line in Terminal, this is what I get.

rusty@rusty-300E4A-300E5A-300E7A-3430EA-3530EA ~ $ ls -ld ~/.mozilla
drwx------ 4 rusty rusty 4096 Feb 8 08:23 /home/rusty/.mozilla


When I enter this is what I get.

rusty@rusty-300E4A-300E5A-300E7A-3430EA-3530EA ~ $ [CODE]ls: command not found
rusty@rusty-300E4A-300E5A-300E7A-3430EA-3530EA ~ $

Is the really what you called your system?
What filesystem type did you use?
What language?

I did not call it anything.
Linux did that all by itself when I installed it.