Files not backed up

WD External and Portable SSD External SSD for Windows
1

I have two excel files that didn’t back up.  the reason stated is object refrence not set to an instance of an

object.

I had my book  unattached from my computer for a while and reattached and did a back up,.  These  files always backed up before.

Can anyone help me with this problem. These are two very important files.  Thank you

2

Try moving the files to a different location on the computer and see if the problem persist.

You can visit Microsoft support for more information about this error message.