My basic question applies to encryption on Mountain Lion 10.8.2 both via Time Machine and through Finder. I am using a couple of 640GB Western Digital My Passport Studio Drives.
First, setting up Time Machine - if I follow the instructions listed at http://support.apple.com/kb/HT1427, when I tell Time Machine to encrypt the newly formatted drive - in Disk Utility, as Mac OS Extended (Journaled) - it performs the backup for an hour and then spends over 12 hours (cannot quite recall how long, it does not matter) performing the encryption. However, if I first of all format using Disk Utility as Mac OS X (Journaled, Ecrypted), which takes 20 seconds, Time Machine performs the backup and then appears to be complete. I tried to restore some files and all seems fine. My question, then: is there likely to be an encryption of restore problem with this latter approach, which saves half a day of processing?
Second, a related question with encryption via Finder. If I format in Disk Utility as Mac OS Extended (Jornaled, Encrypted) it takes the 20 seconds. If I format as Mac OS Extended (Journaled) and then use 'Encrypt...' via Finder, again, it seems to be taking many hours (dskutil cs list in Terminal is showing 4% done after half an hour or so). Again, why not simply format the drive as ac OS Extended (Jornaled, Encrypted) and save this rigmarole? I am concerned that doing it the 'format as encrypted' way there may be some problem with the outcome, otherwise I am unsure why Apple would recommend this approach. I should appreciate any thoughts people have.
Incidentally, this encryption process is ongoing, but when I right-click the disk on my Desktop the pop-up menu shows (greyed out) 'Decrypting 'DiskName"...', when it is in fact encrypting. I wonder why?
Finally, the reason I know all this is that I have gone through the process more than once, not entirely by choice. The firmware in the WDC drives was 10.09. Their updater (available at the link below) could not find the drive (that it had previously identified) whilst it was encrypted with FileVault. I reformatted to Mac OS Extended (Journaled) - this was quicker than doing a 12-hour decryption that may not have worked anyway - updated to firmware 10.12 and am now re-encrypting. Apparently, Mountain Lion does not play too well with earlier firmware versions, so feel free to learn from my lesson.