Windows 10: Why did Microsoft File History not backup all of the files in my Documents folder?

My hard drive failed. I have manually backed up regularly using MS File History. When I tried to copy the files from my backup drive to another computer, I discovered that many many files were missing. For example, a folder might contain a random selection of files. Another folder contains only files created within the last year. I am using Windows 11 on both the computer that failed and the computer to which I tried to transfer the files. Both were set up to update Windows software automatically. How did this happen?

:)

 

Backup These Folders in File History

My Pictures and My Videos folders are inside the My Documents folder. In File History all three folders are listed in the Backup These Folders list. Does this mean that because of this, files in Pictures and Videos are backuped twice? Once when backing up
My Documents and once when backing up My Pictures and My Videos (included in My Documents)

 

File History Folders in Documents

I tried tinkering with File History and couldn't get anything to work: my issue is that I don't want to save all files within my documents folder. I only want to backup very particular files; however, after removing all of the preset folders and added
what I wanted, I found that any folders that are housed within my documents folder don't appear in the backup options. The only time I can see them in my list is when I re-add the documents folder. If I remove the folder again and try to run the backup, there
is an unspoken error and it just doesn't run the backup. I have numerous folders under documents that have been created by various programs and I don't want to go through each individual folder to exclude them nor have to worry about a new folder popping up
and automatically being added to my backup prior to excluding it. Any ideas?

 

Microsoft File History Backup

I recently started using File History back. All seems to work well except my Music Files. I have a large collection of music stored in the Itunes and Amazon folders. But when the backup was executed, not all music folders within these two folders were
transferred to the backup. I can not understand why some were backed up and others were not. Does anyone have any suggestions? All document files are archived fine.