safe to rewrite MBR?

[Andre]

Is there a chance of losing file/directory structure if I
perform a fixmbr command from the recovery console on
win2k?
What about the fixboot command?
thanks for your help

 

[Joseph Conway [MSFT]]

Here are the basic ways that these two commands can hurt you:

FIXMBR rewrites the MBR on drive 0. If the MBR that resides there is
non-standard or doesnt have a 55AA ending sector then a new MBR will zero
the drive, effectively formatting it.

FIXBOOT rewrites the backup boot sector to the current boot sector, it can
only hurt you if the backup contains information that is incorrect (like if
you used Partition Magic and we're pointing to a different boot sector as
the backup).

All in all both commands are "generally" safe.

 

[Andrew]

problem is that I have two drives in my system, one is an ide drive with
winme on it, the other a scsi (id 0) system with win2k.
For some reason, ntldr and ntdetect were installed onto the C (ide) drive,
whereas I thought that all win2k files would have been on the D (scsi)
drive.
I disconnected the ide drive alltogether and can't boot win2k anymore - I
get a message in the bios complaining about a problem booting from previous
device (which is the scsi drive).
I thought that maybe the mbr was messed up and when I used the recovery
console, I could see:
? 0mb partition 0
c:\winnt 8973mb partition 1
? 8mb partition 0

I then used the fixmbr and I got a warning, but went ahead anyway (I was
feeling adventurous). After that, I still couldn't boot to win2k. Plugging
in the ide drive enables me to run win2k without any problems.
I would like to not have to depend on that ide drive for booting.

thanks for your help

 

[David Bullock [MSFT]]

Hi Andrew,
Neither fixmbr nor fixboot is going to help with that problem. Your boot
files were on the C: drive, which is now physically disconnected, so we have
no boot files to get into Windows.

The boot files (NTLDR, NTDETECT.COM, and BOOT.INI) *must* be in the root of
the active partition for Windows to boot. Also, it seems logical to assume
that the old C: drive was the active partition, so the remaining drive must
be made active (you can use FDISK to make the partition active - don't
change or remove the partition, JUST mark it active).

You can then put the boot files on a floppy, use this floppy to boot the
system, and then copy the boot files to the root of your active partition.
The only problem I'd anticipate with this solution is that you might have to
edit the ARC path in the boot.ini file to point to the correct Windows
partition.

--

David Bullock, MCSE, MCSA, A+
Windows NT/2000/2003 Setup Support

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