Can't boot from time machine disk

[pestumepse]

According to the last bullet on this page, external drives containing time machine backup should be bootable and appear as EFI Boot on the Startup Manager screen. My MBP late 2011 is running lion 10.7.5. I formatted a new external hard drive to HFS+ encrypted by erasing the drive using disk utility, and its map scheme became GUID automatically after the erasing operation. After time machine created a full backup on the drive, disk utility even shows it's bootable on its disk info page. However I still don't see an EFI Boot option on the startup manager screen nor on the startup disk preference screen. I'm not sure if it's because my MBP is too old or I missed some important step. Any advice would be appreciated.

By the way, backup content is fully accessible in macOS Recovery so the drive itself should be fine.

 

[cobracnvt]

just a low probability guess, but maybe try it without encrypting the drive initially through disk utility.

 

[treekram]

I have a MacBook running Lion (hardly ever used) but I probably re-purposed the TM disk and only have a clone so what I'm showing is a TM encrypted disk that was created in Mountain Lion but used as the computer was upgraded to Yosemite and then El Capitan.

Using the Terminal app, enter in "diskutil list" and press the Enter key. You should have an entry like the following:

/dev/disk3 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *750.2 GB   disk3
   1:                        EFI EFI                     209.7 MB   disk3s1
   2:          Apple_CoreStorage MiniBak                 749.8 GB   disk3s2
   3:                 Apple_Boot Boot OS X               134.2 MB   disk3s3

[Information about /dev/disk4 removed]

/dev/disk5 (external, virtual):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS MiniBak                +749.5 GB   disk5
                                 Logical Volume on disk3s2
                                 XXXXXXXXXXX-326D-46BB-AE4A-XXXXXXXXXX
                                 Unlocked Encrypted

The /dev/disk # you have will probably be different. The Apple_Boot partition is what will make the disk bootable. See if you have that. On a High Sierra computer I have, also with an encrypted TM backup, I don't see the disk in System Preferences but it is there at startup (not as an "EFI Boot", but with the disk name and the Time Machine disk icon) by pressing the Option key. If your diskutil list output deosn't look like the above, post it.

 

[Weaselboy]

I formatted a new external hard drive to HFS+ encrypted by erasing the drive using disk utility

Yeah... that is the problem. An encrypted TM backup disk is not going to be bootable.

 

[treekram]

In doing additional testing, this is what I've observed.

- The additional partition "Apple_Boot Boot OS X" is only there on my encrypted TM backup disks - it is not there on an unencrypted disk. On an unencrypted TM disk, the files to boot are there on the HFS partition, not in the EFI partition. I was able to boot from it into something similar to the Recovery Utilities menu.

- On one encrypted disk, as I mentioned in my post, the TM disk did show up on boot. It asks for the password early in the process. After going through a boot process that takes several minutes, I get the circle with the slash - so it has problems booting the disk. But looking at the way the disk is partitioned with an encrypted disk vs. an unencrypted disk and the files that are on this extra boot partition, it would seem that Apple's intention is (when working) it should be able to boot from an encrypted disk. The extra boot partition is not encrypted.

- On another encrypted TM disk, the extra boot partition was there but the files needed to boot weren't there.

- On yet another encrypted TM disk, the TM disk showed when booting but when asking for the password it said "[Update needed]". I stopped there - I might go forward to see what happens later. This was the disk which started as a Mountain Lion TM backup and it appeared the boot files there date to 2014, probably as part of the El Capitan update (I'm guessing).

So to me, it appears that theoretically you should be able to boot from a encrypted TM disk but the implementation is erratic. On the encrypted TM disk which has the extra boot partition but no boot files in that partition - it was the initial backup for what is going to be off-site backup so I'll just start from scratch there and redo the backup and see if boot files show up. If it can successfully boot, I'll try to do a file compare with the disk that doesn't boot.

 

[Weaselboy]

@treekram booting from a TM disk at all under El Capitan is borked. Apple fixed it in Sierra and later. So that is likely impacting your testing.

I think even outside of El Capitan the best you could hope for would be booting from the recovery partition on a TM disk, then using Disk Util to unlock the disk, then use Disk Util to restore the image. But I have never been able to do that in testing either (I want to say I played around with this under Mountain Lion).

 

[treekram]

@treekram booting from a TM disk at all under El Capitan is borked. Apple fixed it in Sierra and later. So that is likely impacting your testing.

I think even outside of El Capitan the best you could hope for would be booting from the recovery partition on a TM disk, then using Disk Util to unlock the disk, then use Disk Util to restore the image. But I have never been able to do that in testing either (I want to say I played around with this under Mountain Lion).

The disk that said "[Update needed]" had it's last backup done in El Capitan, but I was using a High Sierra computer to try to boot it from. So maybe the "[Update needed]" will fix it? I don't know if it's worth the effort to find out. The other backups I mentioned are High Sierra backups tested on a High Sierra computer.

So I did find my encrypted Lion TM backup of my 2007 MacBook - I had added another partition to it. I also tried to do a TM backup (encrypted) from my (ancient) 2007 MacBook running Lion. It said it was going to take 7 hours (or 60GB) so I stopped that. In both instances, it created the additional boot partition but there were no files in either of them. I don't know if that's what's going on with the OP, since their disk shows as being bootable (which mine doesn't), so there maybe some other issue involved.

I would agree that with all of the issues, it's just better to figure out another way to do a boot for the purpose of doing a TM restore. But you'd have to get a Lion Recovery partition onto the TM disk - it isn't done automatically from what I see.

 

[treekram]

So it turns out that the additional "Boot OS X" is created every time you encrypt a disk (unless there's no free space left) - at least that's what I'm seeing on my non-TM, non-boot encrypted disks. So I guess Apple put it there in case you want to turn it into a boot disk at some later point? In all but one case on my encrypted disks, this partition was essentially empty.

Thus, when I assumed that a bootable OS was put on a encrypted TM disk, it was based on looking at the one disk I had that had the files to boot (coincidentally it was the first disk I looked at). It turns out that this was a High Sierra backup that was originally a Sierra backup created in 10.12.4. (High Sierra did not touch this partition that's why the files were still there but the dates on the files and an attribute in a plist indicate that it was done in 10.12.4). I created (twice) a new TM disk on my Sierra 10.12.6 MBP and boot files are not there. I could try to do a 10.12.4 install and see if it can create a properly bootable encrypted TM disk but that's an academic exercise at this point.

So the moral of the story is in order to restore to a new disk from an encrypted TM disk, which Apple did not explicitly cover in the document that the OP posted in the first line of his original post, in most cases you will either need to rely on Internet Recovery, a bootable OS disk, or a bootable installer or Recovery disk/flash drive. One option you cannot do is put the Recovery partition into the "Boot OS X" partition that gets created on the encrypted drive as this is 134MB and the Recovery partition is much larger - 478MB for Lion, 550+ for High Sierra. You could resize the partition devoted to the TM backup but that's just not prudent, IMO. Better to make a bootable clone (especially if you don't have a Recovery partition) or copy an existing Recovery partition for the OS in question to a flash drive and make it bootable.

 

[Fishrrman]

IF the OP had used either CarbonCopyCloner or SuperDuper to create a BOOTABLE cloned backup (instead of relying on Time Machine, which has failed him), he would have access to that data right now.

OP:
Try either of the above to prevent yourself from ending up in a similar situation again.
Both are FREE to download and use for 30 days.
Trying them COSTS YOU NOTHING.
SD will create a bootable backup (without registering) FOREVER -- however you cannot do incremental backups UNLESS you register it.

 

[treekram]

IF the OP had used either CarbonCopyCloner or SuperDuper to create a BOOTABLE cloned backup (instead of relying on Time Machine, which has failed him), he would have access to that data right now.

OP:
Try either of the above to prevent yourself from ending up in a similar situation again.
Both are FREE to download and use for 30 days.
Trying them COSTS YOU NOTHING.
SD will create a bootable backup (without registering) FOREVER -- however you cannot do incremental backups UNLESS you register it.

There's nothing in the original post (the OP hasn't made a post since) which says the Time Machine backup failed. Rather, it appears the OP admirably took the effort to see if a newly-created encrypted TM backup would actually boot, not relying on the ambiguous Apple document which states that a TM backup can boot.

I agree that having a bootable clone (with the Recovery partition) even if one has a TM backup is a good idea.

For the OP - since I re-read the original post, it appears you're going to rely on Internet Recovery to boot and restore via Time Machine. If you don't go the bootable clone route, I would still make sure I had a secondary way to boot and restore the TM backup - such as putting the Recovery Partition on a flash drive. Even though I hardly ever use my Lion MacBook and I have a bootable clone and a TM backup, I decided to take my own advice and I imaged the Recovery partition onto one of my HDD's for possible future use. Of course in my case, I don't think the 2007 MacBook can do Internet Recovery.

 

[pestumepse]

Sorry for the late response. Thanks everyone for your insights, especially to treekram for taking the time and effort in doing all the testing. Below is my diskutil list output in case you’re still interested.

/dev/disk1
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *2.0 TB     disk1
   1:                        EFI                         209.7 MB   disk1s1
   2:          Apple_CoreStorage                         2.0 TB     disk1s2
   3:                 Apple_Boot Boot OS X               134.2 MB   disk1s3
/dev/disk2
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS Seagate Backup         *2.0 TB     disk2

Not surprisingly, the EFI and Boot OS X partitions on my external drive are of the same sizes. The recovery partition on my internal drive is 650 mb though. Anyway based on what’s been observed, it seems that making TM disk bootable is never a priority for Apple so they didn't really think it through when they made the claim. Encryption on disks probably just adds another layer of complexity. I'm thinking it would be nice if TM (maybe together with disk utility) can automatically create a recovery OS partition unencrypted and a backup partition encrypted on a target drive. I don't know how difficult it is.

Btw just to clarify, I still have access to all my files. Actually I was preparing to replace my old HDD with a new SSD. I was hoping I could simply boot from TM disk and format the drive then restore my files in case Internet recovery failed me (as I heard you have to remember the AppleID you used to set up your MBP at the very beginning, which I don't). I knew there’s various ways to achieve that but the idea TM disk is itself bootable sounded very appealing and handy so I decided to figure out how. Ironically it is not nearly as straightforward as Apple states. I am going to try to reformat my external drive as unencrypted and see how it goes.

 

[Weaselboy]

I am going to try to reformat my external drive as unencrypted and see how it goes.

That should work for you and be bootable. I think the encryption is what is complicating this for you.

Just format to HFS+ and attach the drive and enable TM on it and the first backup will put a recovery partition on there. You don't need to do anything special.

 

[treekram]

If the main goal at this time is to copy the files to the SSD, I'd just use clone software - CCC or SuperDuper and an external USB enclosure. I haven't used either but people say good things about them. You'd have to make sure you have the right version of software for Lion. Both have free software with limitations but you'd have to check if that applies for the version for Lion.
https://bombich.com/

A second option is to boot into Recovery and you should be able to target the SSD (in an external enclosure) for the restore.

Or you can image the Recovery partition to a USB flash drive and then use the encrypted TM disk booting from flash drive. The Recovery partition isn't typically visible in Disk Utility to image so if you need information on making the image, just ask (I typically use the command line but you should be able to do it with Disk Utility). I just tested that out a few days ago for my Lion computer and it was able to boot (didn't attempt an actual restore, though).

BTW, on my El Capitan TM backup, to my surprise, this encrypted TM backup was able to boot into what you see in the Recovery Utilities. The Disk Utility app worked but I didn't try restoring.

EDIT: A Time Machine restore won't re-create the Recovery partition on the target disk. CCC will do that.

 

[Weaselboy]

A Time Machine restore won't re-create the Recovery partition on the target disk.

As long as the TM disk is not encrypted causing all these issues OP is having, and standard backup with TM to an external local (USB) drive will have a recovery partition on it, and a restore from that disk will put the recovery partition back on the internal drive.

 

[treekram]

As long as the TM disk is not encrypted causing all these issues OP is having, and standard backup with TM to an external local (USB) drive will have a recovery partition on it, and a restore from that disk will put the recovery partition back on the internal drive.

I just tried the following (Lion):
- Booting from Recovery on flash drive
- Using encrypted external TM HDD
- Restoring to external HDD (non-encrypted)
That didn't put a Recovery partition on the HDD. So once again, there's some inconsistency here. Although it's not a big deal to get a Recovery partition on a disk that doesn't have one - provided you have enough space and haven't done too much with the disk.

For the OP, my opinion would be that if you prefer to keep your TM disk encrypted, you shouldn't go through an unencryption and encryption process just to be able to boot from the disk and get the Recovery partition on the new disk - there are other alternatives available.