Mailing List Message #15636
From: Bill Cole <>
Subject: Re: Final task
Date: Tue, 02 Jun 2009 19:04:07 -0400
To: SIMS Discussions <> wrote, On 6/2/09 3:44 PM:
You are correct - there is a disk issue - but only with 1 account - all
other accounts are fine and I can copy them. When I try to copy my
account to another box, I get error -50 can't be copied. There is
probably come corruption but it's hard to find repair utilities for MAC
OS 9 still around.

Thanks for the help. If I can find some utility to repair the file and
let me copy it - i will use the command you sent.

Apple's Disk First Aid will very rarely fail where other MacOS 9 utilities can do anything useful in recovering a corrupted disk. You can still download DFA from if you don't have it already.

Among the third party utilities, Alsoft DiskWarrior can sometimes recover a corrupted disk where DFA gets lost. I would not bet on it in this case, but if you can find a copy that will run on OS9, it would be worth trying if DFA fails on a logical problem. If you can dig up a very old Norton Utilities, it had a very low level scanning function that can reconstruct some files, but it is extremely slow and frequently yields more junk than usable files.

If you can get the disk connected to a OSX machine, Apple's Disk Utility is still the best first thing to try, although again DiskWarrior would be the second line tool. Ultimately, the 'dd' utility (a classic Unix tool) can be helpful in extremis if you absolutely positively must get everything recoverable from a dead disk that will not mount and can't be fixed due to hard errors. The process for that is slow and profoundly geeky: you can use dd to do a block-by-block copy of the disk (null-filling unreadables as you go rather than failing or skipping them) onto a non-failing disk, then using Disk Utility on the result to clean up the filesystem on the new disk. If you get that desperate, let me know and I'll go digging for the exact commands I used to recover a disk that way a few years ago...

A -50 error is often a sign of total hopelessness, particularly when seen mixed with -36 errors. Typically an app will get a -36, and the Finder will take a longer time to give you a -50. The reason for that is that the Finder has fallback approaches below the filesystem that it tries after getting a -36 from the normal file open call, and the lower level calls yield a -50. Occasionally you can get that from flaky SCSI or unusual forms of filesystem corruption that include file cross-links, but most often it means that the disk used up its supply of spare sectors (that are used for invisibly remapping borderline sectors) at some point far enough in the past that you've managed to get a solidly unreadable block allocated to a file that you want to read. This is very much a case of walking on very thin ice with that disk: it may or may not have a very large number of sectors that are marginal or bad, but statistically you are very unlikely to just happen to find the only one.

Bottom line: This error pattern is an evacuation notice. Do not trust that disk.
Subscribe (FEED) Subscribe (DIGEST) Subscribe (INDEX) Unsubscribe Mail to Listmaster