For me the errors occurred when checking VFAT drives on startup. The 
drives were not reported to have any errors during previous Windows Me 
session.
Win Me "Scandisk" did find (and fix) lots of errors after being "fixed" 
by dosfsck. In the process I lost 256 Mb of disk space.

All errors seemed to be with files with long file names including a 
space somewhere in the path.  eg C:\My Programs\MSACCESS.EXE or 
F:\Letter to fred.doc

(I can't remember where that information came from - whether it was from 
dosfsck reporting the errors it found or from Scandisk fixing dosfsck's 
errors - I think I identified it in my original bug report)

During the installation, while preparing to partition the disk, the 
installer "checks discs for errors" and, if it finds "errors", asks 
politely if you want them fixed. If the installer passes this stage 
without detecting errors, the install seems to succeed. If you find 
errors and proceed to install without letting dosfsck fix the "errors", 
at the first system reboot, dosfsck will "fix" the "errors" without asking.

On another installation attempt, dosfsck reported errors, I aborted the 
install and ran scandisk under Windows. Windows DID find one error on 
each disk that dosfsck identified and  no errors on disks that dosfsck  
declared  to be OK.

So it appears that dosfsck might be correctly identifying errors but 
making things worse when trying to fix them. Hope this narrows the 
search for the bug(s).

So, it would seem possible to duplicate the bug by deliberately creating 
errors in a VFAT file system, probably in files with spaces in the path. 
It should be possible to create VFAT disc errors by opening and editing 
several files in wordprocessors / spreadsheets etc then resetting the 
computer (without proper shutdown).
 
I haven't had any problems with ReiserFS, ext3 or ext2 filesystems.

StefanPotyra wrote:

> *** This bug is a duplicate of bug 48806 ***
>
> Hi,
>
> this is in fact not one bug, but three:
> 1) dosfsck is buggy
> 2) other file systems are checked during boot
> 3) file system checks depend on a buggy program
>
> I'm pretty much interested in fixing 1). So any useful info how
> reproduce this are highly appreciated.
>
> As I'm most of the time just a user of ubuntu, I'm not interested in 2)
> and 3), because for me it just works. However here are some comments to
> these, but these reflect only my humble opinion:
>
> 2) please define "other file systems":
> I have a ext3 FS which I use to store various data on. It's neither vital nor in any way necessary for ubuntu to work. Would this also fall under this catagory?
> Imho there is only a point in making a distinction between rw-mounted file systems and ro-mounted ones.
>
> 3) that's a serious bug indeed, fixing the installer would fix that. Of
> course fixing 1) would also fix that.
>
> I don't think that the warning thingy might get us anywhere closer. For me personally dosfsck never ate any files, so you'd make me unhappy if I suddenly couldn't write to my fat32 partition or in case it does get corrupted if it wouldn't be fixed on boot.
> However other bugs have shown that dosfsck is indeed buggy, and with the help of the submitters I could provide a fix for some of these.
>
> Thanks,
>     Stefan aka sistpoty.
>
>   



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