Can I make a (OS X 10.11.5) TimeMachine backup HD bootable?

[ranger1]

Hello all,

After endless problems with El Capitan (on Mac HD) not working with a great many non Apple softwares, I erased the internal HD and installed Yosemite 10.10.5. Unfortunately, I did not drag my Mail folders etc. onto a second (non TimeMachine connected) external 2TB HD. Similarly, all my Safari bookmarks were also lost.

However, my 500GB external HD was used by El Capitan (running on Mac HD) to TimeMachine backup the internal HD, I thought that all data files etc. must be backed up on that 500GB HD, including all System files, Libraries etc.

Can I somehow make that former El Capitan backup HD a startup disk. I could then (from Yosemite internal HD) change System Prefs/Startup Disk panel to startup from that former TimeMachine HD and drag (belatedly) all the 'lost' Mail folders onto the 2TB external HD. I could then reboot from the newly installed Yosemite internal HD and drag the 'saved' Mail folders into the Yosemite's Apple Mail.

I am grateful for any advice you may have.

Sincerely, ranger1.

 

[Cory Cooper]

Hello,

There isn't a way to make a Time machine disk itself bootable. However, you could use an external HD to restore a Time Machine backup to, which would then be bootable.

C

 

[ranger1]

Hello,

There isn't a way to make a Time machine disk itself bootable. However, you could use an external HD to restore a Time Machine backup to, which would then be bootable.

C

Thank you Cory Cooper for your generous response.The El Capitan Time machine backup is 372GB on a 500GB external drive. I have another HD (2TB) which has 1.9TB available. That 2TB HD has Yosemite 10.10.5 installed on it and can be selected as a startup disk.

Do I copy the 500GB HD contents as is directly onto the 2TB (preferably into a new folder to keep the El Capitan backup data separate from other files already on the 2TB HD, please? What I want to do is retrieve my El Capitan Safari bookmarks into the (newly installed) Yosemite Safari on Mac HD.

Thank you again, Cory.

Sincerely, ranger1.