Since I do not have very many changes. I turned off the automatic Time Machine backup. I manually backup using Time Machine once a month.Time Machine has been backing up. But last 2 times it started behaving badly. I can try Disk utility First Aid and see what errors if any I get. In case if I am not able to fix the error by Disk utility First Aid; Only way to continue using the drive for TM backup is to reformat the 2 TB an start over again. by doing this I will loose all my older backup. Is that correct? Any help will be appreciated.