Using my Mac Mini was like wading through treacle so I decided to perform a totally clean install, wipe it and start again. I made a Time Machine backup and let that run for a couple of days to make sure I had everything I needed. Now when I try to use the backup the drive partition that it is on is greyed out. All I need are the photos really, I can see the old Photos library in the backup and even copied it over into the new Photos package but they aren't recognised. Any ideas?