There are several steps that I find essential to preserve folders with files that are not functional for the system itself.
1. Set your programs, such as Word, Excel, etc., to save their files to another partition, preferable on a second hard drive, the idea being to not let the program save them to a folder in the system partition. After producing a Word document, save it to at least two other partitions, on two other drives, if possible. I sometimes still use Turbo Navigator for this purpose. There are doubtless quite a few other such programs available for backing up small numbers of files. You can also just open a window showing the files to be saved and copy them to a destination window on another partition/hard drive using Windows File Explorer.
2. Copy your One Drive folders/files to a backup partition on another hard drive. This saves documents, pictures, videos, etc., that might have been saved to the system partition from having their folder overwritten with no content within, or otherwise lost.
3. Enter the Program Files folder on Windows partition C:\ and locate the email files within your email program and back up your main folder for these up at least once a week. For Thunderbird, this entails following a long trail of sub-folders under the "Users" folder. The .MSF file has to be included for both Inbox and Outbox. This preserves your emails, both sent and received, from being deleted by system restore or even possibly by an upgrade of the email program. If your emails are lost, you can simply copy the backed up Inbox, Outbox files (with .msf files) to the freshly restored email program.
Since you might have lost valuable documents by using system restore (?), you could search around to determine what has been lost and what else might still be there. This gives you an idea as to what needs to be backed up regularly. In my view, the only way you can be sure that your documents, pictures and downloads will be saved from an unwanted deletion is to copy them onto backup partitions. If the product manufacturer decides to get rid of unnecessary files from its perspective, without consulting the computer operator first and offering an option to save all existing files, then it bodes well to pay heed to the disclaimer window that usually pops up advising the user to back their files up before installing, upgrading or repairing.
If anyone else knows of a program that will copy preset file folders and files directly to a backup file folder, whenever you simply mouse-click for a pre-set copy routine, please let me know. It would be nice if the save by copying to a backup partition or two was that easy.
