One way to backup your TTP database is using MS SyncToy - it will copy your important TTP files and make sure you can roll back to a "good point" in time if you run into problems.

You can also use a Zip utility - like 7zip - to do the same thing and create backup versions; or do both!  You can never have too many backups when working with valuable computer data.

First step is always to shut down TTP to make sure the databases are properly closed and not locked.  From the System Tray icon for TTP; choose the Shutdown option.

MS Sync Toy is available from the Microsoft website for free:

Here is a screenshot where we have setup a "folder pair" - where the left folder is synchronized with the right folder.  In this case, the TTP Appdata folder is backed up to a removable USB drive (E:\):