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Restoring MBR

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Whenever I restore C:, I am asked whether or not to replace the MBR and where to put it. Why would I want to make this choice? Isn't the MBR part of C:? If it is not part of C: then why is it backed up along with C:?

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It isn't always necessary to replace the MBR. It depnds on which partition you are restoring on a drive.

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Stuart,

The MBR is part of the disk, whereas C: is a partition on the disk. The information describing the fact that your disk has that C:\ partition is contained in the MBR.
You typically choose to restore the MBR when your boot record has been overwritten or damaged, of course, or when you have a brand new disk (useful when you have a multi-OS computer, for example). Just make sure you include your entire disk in at least one backup you will feel comfortable going back to in case your disk completely dies.

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Thanks for your comments. I think I understand correctly that if you want to replace the MBR it would have to be from a clone. This brings up a related subject that should be in a new thread. I'll call it "Using a Clone to Replace a Drive".

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Wait... Restoring the MBR doesn't have to be from a clone. A clone will include the MBR, sure. A full disk and partition backup will containt the MBR if you select the entire disk to be backed up.

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There's a little bit of confusion apparent here. Although the "MBR", or the first sector on a disk, does contain the partition table with information about the number, size, and location of each partition, TI does not restore the partition table when you restore the MBR. When you restore the MBR you do not re-create the partition layout on the disk.

There is another explanation of how the "Restore MBR and Track 0" function works in TrueImage in this thread: http://forum.acronis.com/forum/13539

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Mark,

OK. I have edited my earlier post to correct it.

Something I don't understand then. Recently, I user the Acronis drive cleaner before a restore. Then I restored with the MBR and Track 0. A couple of questions:
- did the drive cleaner erase the MBR? Completely or partially? Did it leave the partition table?

If it left the partition table, that makes sense.

If it didn't, how did the partitions got re-created? I understand the ATI writes/updates the partition type in the partition table entry corresponding to the partitions that it restores. Does it create an entry (and therefore a partition) if there is none?

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Mark Wharton wrote:

There's a little bit of confusion apparent here. Although the "MBR", or the first sector on a disk, does contain the partition table with information about the number, size, and location of each partition, TI does not restore the partition table when you restore the MBR. When you restore the MBR you do not re-create the partition layout on the disk.

There is another explanation of how the "Restore MBR and Track 0" function works in TrueImage in this thread: http://forum.acronis.com/forum/13539

Mark,
When reading the thread you referenced (http://forum.acronis.com/forum/13539), in your post # 14, I will admit to being somewhat confused!

I use TI 2010, build 7046, to do weekly disk level image backups of my boot disk containing drive C: (Win 7) and drive D: (working data). Two other disks containing perminant data are backed up by other means. Going from XP, I could not do an upgrade to win7, had to scratch install.

Question is -- If it becomes necessary to restore from my boot disk image, will TI convert my disk from 2048 to 63 sector boundaries, but still function normal? (I assume, as you described, that the win7 install created 2048 sector boundaries!)

If I have a mix of sector boundaries among my disks, does Disk Director 11 (designed compatable with win7) handle any partition adjustments I may need to make with the mixed formats?

Thanks for any comments.... Bob

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Pat L:

I don't know exactly what Acronis Drive Cleaner removes; it may leave the NT Disk Signature and generic boot code, but I'm not sure. But certainly it would delete the partition table.

You are correct - as TI restores each partition it writes a new partition table entry for the partition.

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Robert:

I'm a long-time user of TI version 10 (not 2010) from several years ago, and my comments in the post that you referred to were true for version 10, which always used the 63-sector offset partitioning rules when restoring partitions. I've only recently begun using TI 2011, which has a different algorithm for determining which offset to use. I do know that if you back up a Vista or Windows 7 partition that was created with 2048-sector offset and then you restore to an existing partition on the disk that has 2048-sector offset, the offset will be preserved. I haven't yet figured out what it will do under different combinations of circumstances, but perhaps MudCrab or one of the other experienced users can fill in the details.

As for DD 11, it does offer the user a choice of partitioning rules, but to see the choices the program has to detect an installed operating system. For example, if you have only Windows 7 installed then you will see only one choice - use Windows 7 partitioning rules (2048-sector offset). If you have disks with both XP and Windows 7 installed then you can select the rules to use; XP or Win 7 (63-sector or 2048 sector).

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Mark Wharton wrote:

Robert:

As for DD 11, it does offer the user a choice of partitioning rules, but to see the choices the program has to detect an installed operating system. For example, if you have only Windows 7 installed then you will see only one choice - use Windows 7 partitioning rules (2048-sector offset). If you have disks with both XP and Windows 7 installed then you can select the rules to use; XP or Win 7 (63-sector or 2048 sector).

Mark..
I don't wish to beat this to death, but to clarify:
I currently only have win7 system installed, but I do have disks and partitions created when running XP, prior to converting to win7. That conversion from XP required system disk initialization and scratch install of win7. I assume that resulted in creation of 2048 sector offsets on the system disk partitions. I assume the other two disks were left unchanged (63 sector offsets) -- therefore my question about dd 11. If dd11 sees only win7 OS installed, I think you are saying it will treat all disks and partitions as having 2048 offsets. So, my concern is -- what would happen using dd11 to adjust partitions sizes on these two disks??

And, YES, I am aware of the warnings about ASSUMPTIONS!! But, at the time of installing win7 on my system, I knew nothing about 63 vs 2048 offsets, or I may have done some things at that time to avoid this concern, like reformat and reload those disks as well. Perhaps I should do that now!!

Mark, I really thank you for, and value, your sharing your experience and expertise. I am sure many others do also!!

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Same thing here, Mark. Thanks a lot... Learning something everyday.

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Robert:

I don't have a Windows 7 VM here at work to experiment with, but I have an XP VM. So I couldn't test your situation with a Win 7 OS and DD 11 modifying Win XP-style partitions. But I can do the opposite - a Win XP OS and DD 11 modifying Win 7-style partitions.

The XP VM has a main disk (Disk 1) that was partitioned with XP, so it has 63-sector offset. I created another virtual disk (Disk 2) with 2048 sector offsets and two partitions to use during tests. When DD 11 is running it detects Win XP as the installed OS and offers Windows XP SP3 as the only choice for the disk layout, so I presumed that it would use XP rules when modifying the partitions on Disk 2. I quickly tried several operations - resizing, moving, deleting, and creating partitions. In all cases DD 11 maintained the 2048-sector offset on Disk 2. I don't know why, but it did.

When I modified the partitions on Disk 1, DD 11 maintained the 63-sector offsets on that disk. So apparently it must check the existing partition table before determining which disk layout to use. However, I wouldn't want to base any conclusions on such a cursory test.

To answer your question then, I THINK that DD 11 would keep the existing layout rules on your XP-formatted disks if you modify any of their partitions. If you want to switch completely to Windows 7 rules so that you have a consistent set of disks that can be readily modified with Windows 7 tools then it may indeed be worthwhile to remove your data from the disks, re-create the partitions, format them, and copy the data back.

If you want to check which offset is in use, just examine the partition table with DD 11. Click on the icon of the disk itself and then choose "Edit Disk". When the disk editor opens, change the view to "As partition table" as shown in the example below from an XP VM. The "Relative Sectors" column should be 63 or a multiple thereof for a 63-sector offset partition layout and 2048 or a multiple thereof for a 2048-sector offset layout. The "Number of Sectors" column should be a multiple of 63 or 2048, respectively. The example is showing the partition table of the XP system disk, Disk 1.

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Thanks much, Mark, as always.......
Bob

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You're welcome, but I don't think that we resolved anything. I've posted in the MVP forum a suggestion that DD 11 should have a way to explicitly choose which layout to use, instead of relying on some OS detection algorithm. I, for one, would like to be able to KNOW which layout will be applied before committing a change. Right now it's guesswork.

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Hello again, Mark....
Well, the saga continues! I took your suggestion in post #12, and checked the sector offsets on all my drives. What I found means I must revise some info I put in post #10 -- it seems ALL my drives, even the system disk, have 63 sector offsets!! I must have formated the drive BEFORE installing Win7 rather than having the install CD do the format.

That raises a concern about my system image backups. I admit to not knowing the inner workings of TrueImage, so I don't know what to expect if I need to restore from a backup image file, saved from a disk with 63 sector offsets. If the image save format is determined by what windows version ATI finds, does existance of only Win7 mean a backup image will expect to see a target drive with 2048 sector offsets during a restore? I sure don't wish to find an invalid situation if/when I need to depend on that backup image!!

In order to feel confident with all this, I may go to the trouble to use one of my data drives to copy everything off, let Win7 format with 2048 sector offsets, and restore the most recent image to it. If that works, and the disk retains the 2048 offset format, and the system boots from that disk and functions normal, I will use that disk as system disk and then convert the other disks to 2048 to use for data (so as to have a consistent set of disks as you suggested in your post #12). If that restore fails, I am not sure what action to take, but now is the time to remove these concerns instead of at the time of a disaster sometime down the road!!
Thanks again for all your help. Bob

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Bob:

With TI 2011 you should be OK. I believe that the algorithm used in TI 2011 is to keep the currently-existing offset if you restore to an existing partition. That would mean that you could restore your images to disks with existing 63-sector offset partitions and the offset would be retained. It also means that if you create new partitions on the disk with 2048-sector offset and then restore your images to the new partitions, the 2048-sector offset would be retained.

Two of my desktop PCs are still using 63-sector offset partitions, and both Vista and Windows 7 are fine with that, although you have to remember not to use Windows Disk Management to modify the partitions (I've been using DD 10 for that task). I converted my laptop to 2048-sector offsets when installing an SSD. I did this by using DiskPart from a Windows 7 boot CD to create the partitions, and then restoring images to the new partitions. However, as a disclaimer, the images were from Windows Home Server; not from TI. But the principle is the same.

Your proposed plan to convert your partitions to 2048-sector offset should work, but have a Windows 7 recovery CD on hand in case the new disk fails to boot. An automatic repair (which you may have to run more than once) should fix any boot problems if they occur. TI 2011 is supposed to contain code to automatically fix the Windows BCD when restoring to a different partition, so the repair is not supposed to be necessary.

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I have Acronis True Image 17 and have had this backing up drive C onto a separate 1TB drive (E) since dat 1. In the past  I have had to recover the odd files which is easy.  Something corrupted my MBR on drive C so I dug out my original drive C which still has TI17 on it and I made a CT recovery CD.  The faulty drive is now back in place but I am not sure how I can just recover the MBR from the backup.  The CD recovery choices are a little confusing (I blame my age!).

Richard

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Richard, welcome to these public User Forums.

You probably do not need to use ATI 2017 to recover the MBR for this scenario.

You haven't mentioned what version of Windows OS you have, but assuming this is one of the more recent versions, i.e. 7, 8, 8.1 or 10, then you mainly will need either a Windows Install DVD or else a Windows Recovery Drive (on USB or Optical media).

If you have Windows 10, you can get more information on the main Settings >> Recovery page by following the link for creating a recovery drive.

See webpage: How to: Create a Recovery Drive for reinstalling Windows 10

Once you have an Install DVD (or USB stick) or Recovery Drive, you would boot from one of these then get to a Command Prompt window and use a simple command - see the following webpage.

Webpage: Repairing A Broken Bootloader Or Master Boot Record In Windows 7, 8, And 10

If you prefer to use ATI 2017 to recover your MBR, then see forum topic: [How to] recover an entire disk backup - and in particular, the PDF document referenced in that topic which shows how to do a full disk recovery, but which has screen images of all the steps involved, where you could elect to just recover the MBR and Track 0 data only, and deselect all other options to recover.