I have a MacBookPro, purchased October 2012. I use Time Machine to back up files. I was having slow computing issues, so the Genius Bar folks recommended a wipe out and reinstall from scratch, but we decided not to back up the entire disk off of Time Machine for fear that it would only put back onto my computer that which made it run slowly. I did full reinstall, reuploaded all software, a bunch of files I kept on an additional external drive, and now need to go retrieve a few files (not a full restore) from the Time Machine back up. I see the purple tag mark for the precise date before I took the computer in, but the machine will not let me click on it to "reveal" that date's back up. Any ideas how I can get back to those files? Thanks
I would try Back-In-Time.
Yes it cost $30 but there is a demo and the couple of times I have needed to dig stubborn files out of a Time Machine backup it worked.