OS X 10.9.5 on iMac 2013 late. No Bootcamp. OS X a originally installed by factory plus all those updates till 10.9.5. One of our Time Machine destinations is an external USB drive, a HDD, not a SSD. Recently drive generates additionally to its typical noises some new noises nor typical for a hard drive. So it is going to raise a RMA on provider and be sent back for replacement or fix. All these backups generated by Time Machine need to be backed up on some other container before the drive leaves our house. We tried to use iMac system disk / volume. Once as normal user, another time as administrator. Every time the result of the copy counts much less items and GB's of size than the original on that external usb drive. Instructions found on pondini.org were followed. How to be sure all of TM backup on external usb drive was copied to iMac internal system volume? Mac OS Journaled partition, case non-sensitive on GPT formatted external usb drive.