The time you had moved the files from M Drive to N Drive out of Lightroom, you might have got exclamation mark.
As the Files were moved from the original location of import, I hope you have reconnected the images to N Drive.
Also if you import some new images from M Drive and move them to N Drive within Lightroom, please see if you are able to see the edits or flags.
I did not get exclamation points because I copied the files to N from M and then imported them into Lighroom from N. Now I dont get the flags. When I move files within Lightroom from one drive to another, then I do get the flags. I want to keep a copy of the files on M drive as a backup but use N drive as the source drive because it has more space. thank you for your quick response.
You have imported the images as a complete new files when importing from the N Drive,
That is the reason you do not see the flags or edit.