I am on an imac with System 10.11.3. When I have mail open and open Time Machine all looks well until I go back in time and now it doesn't show any of my on my mac folders. Never did that before . Present time shows all the folders
21.5 inch imac mid 2011 with 8 GB of Memory
Thanks Mark

Problem resolved more or less. I had the drive plugged into the Thunderbolt port using a firewire to Thunderbolt adapter. When I switched to Straight Firewire 800 it works fine. To the best of my recollection it used to work with both connections. Anyway it is working fine now

Here's a possible cause: A Firewire 800 - Thunderbolt adapter transmits data only one way, namely FW to TB. If you were trying to transmit the opposite way, it wouldn't work.

Are you sure of that, Jon?

I know that Apple's adapter can be used to connect an external FireWire device to a Thunderbolt port on a Mac, and that there's no such thing as a reverse adapter, but I can't find any documentation for oyur (unless I've misunderstood it) statement that such an adapter can't transmit data in both directions when it's used as designed.

Apple's Thunderbolt FireWire adapter is a one-way connector

The interesting thing about what was going on was I could retrieve info from inbox and sent folders. that was no problem. It was that it wouldn't even show the words "on my mac" or any of the folders to store mail that I had created under on my mac. My mail provider is a Pop account from comcast. thus the inbox and sent are on my computer also

Yep, that's what I said, but since MarkG had already posted


i.e. he was clearly hooked up correctly, it sounded like you were saying that even hooked up correctly, data flows only in one direction, so clarification was in order.

From Apple Thunderbolt to FireWire Adapter:

"Easily connect your Thunderbolt-equipped Mac to a FireWire device with the Apple Thunderbolt to FireWire Adapter. Small and compact, it connects to the Thunderbolt port on your Mac computer, giving you a FireWire 800 port that supplies up to 7W for bus-powered peripherals like hard drives and audio devices."

The unidirectional limit simply means that you can't connect your FireWire-equipped Mac to a Thunderbolt device.

Been meaning to thank you for cleaning up my bollixed post.

Well after 2 weeks of experimenting I can get it to work for a day if I delete /Library/Preferences/com.apple.timemachine.plist. When com.apple.timemachine.plist is deleted I can use USB, Firewire, or Firewire with Thunderbolt connector and it works fine for a day and then Time Machine reverts to not showing any of the on my mac folders when I go back in time in Mail. At least I have a work around, but it would be nice to know if it was a bug or something with my machine.