KB920958 causes data loss on compressed folders

Countless Windows 2000 (Pro and Server) users in the UK and US have reported
that KB920958 is causing permanent loss of disk data, if the "compress"
attribute is set for folders.

New files that are close to a multiple of 4K in size will have their last
4,000 bytes or so overwritten with 0xDF (looks like a 'B'). The problem is
not immediately apparent due to lazy caching. However, after a few hours,
once the data has expired from the cache, the damage to the file is visible.

It has been confirmed that either turning off the compression attribute
(disk space permitting) OR uninstalling KB920958 will prevent further loss of
data.

The problem HAS been reported to Product Support but so far I have yet to
see a pro-active announcement by Microsoft warning customers that use the
compression attribute that they will lose disk data permanently.

I have noticed that my graphics will radommly corrupt I checked my 2kPro box
and this file was not installed but my 2k Server box has this update on it.

Leave it to MS

"Andy Schmidt" wrote:

> Countless Windows 2000 (Pro and Server) users in the UK and US have reported
> that KB920958 is causing permanent loss of disk data, if the "compress"
> attribute is set for folders.
>
> New files that are close to a multiple of 4K in size will have their last
> 4,000 bytes or so overwritten with 0xDF (looks like a 'B'). The problem is
> not immediately apparent due to lazy caching. However, after a few hours,
> once the data has expired from the cache, the damage to the file is visible.
>
> It has been confirmed that either turning off the compression attribute
> (disk space permitting) OR uninstalling KB920958 will prevent further loss of
> data.
>
> The problem HAS been reported to Product Support but so far I have yet to
> see a pro-active announcement by Microsoft warning customers that use the
> compression attribute that they will lose disk data permanently.

Hi,

I have opened the online case number:
SRZ060911001854

I recommend doing same.

"War^Lords" wrote:

> I have noticed that my graphics will radommly corrupt I checked my 2kPro box
> and this file was not installed but my 2k Server box has this update on it.
>
> Leave it to MS
>
> "Andy Schmidt" wrote:
>
> > Countless Windows 2000 (Pro and Server) users in the UK and US have reported
> > that KB920958 is causing permanent loss of disk data, if the "compress"
> > attribute is set for folders.
> >
> > New files that are close to a multiple of 4K in size will have their last
> > 4,000 bytes or so overwritten with 0xDF (looks like a 'B'). The problem is
> > not immediately apparent due to lazy caching. However, after a few hours,
> > once the data has expired from the cache, the damage to the file is visible.
> >
> > It has been confirmed that either turning off the compression attribute
> > (disk space permitting) OR uninstalling KB920958 will prevent further loss of
> > data.
> >
> > The problem HAS been reported to Product Support but so far I have yet to
> > see a pro-active announcement by Microsoft warning customers that use the
> > compression attribute that they will lose disk data permanently.

Problem confirmed by Microsoft Support:

"We are aware the issue you are experiencing. A corresponding bugcheck
request is currently open, and the develop team is working on this issue.
However, the hotfix for this issue is not ready.

0xDF is the data pattern that NTFS returns when it has problem to decompress
the file (eg. the compression fragments are corrupted and can't be
decompressed). Based on my research, the actual raw data on the disk is not
changed, it shows as 0xDF because the system cannot decompress the file and
display the data correctly. So the corrupt is not permanent.

Further more, the issue only occurs on files which containing Hexadecimal
codes."