EFS Error in Windows Briefcase

  • Thread starter Thread starter sunshe
  • Start date Start date
S

sunshe

Here is the scenario of the problem, and I appreicate any input from
the community. Thanks.

I have a desktop, a laptop, and a USB hard drive. Both desktop and
laptop are running Windows XP with the latest security updates.

I connect the USB hard drive to the desktop. Created a briefcase to
synchronize files between desktop and mobile hard drive. Enrypted the
briefcase. Exported certificate with private key to the mobile drive
from the desktop.

I then connect the USB hard drive to the laptop. Import the desktop
certificate into the laptop. I was able to open the encrypted
briefcase and access some files. But other files would fail with an
"Access Denied" message.

Here is something more interesting. I re-connected the mobile drive to
the desktop, and re-exported another certificate against the specific
file which failed access on laptop. Then import this certificate again
on the laptop. The file was able to be accessed after the second
certificate.

I have compared the public keys in the two certificates and they are
identical.

Even after the first failed file is fixed using the above procedure,
there are other files still having problem. And I could continue to
fix file one by one by re-exporting certificates. But this is
certainly not practical.

So the main question is: why would some file work and others fail
within the same enrypted directory? According to my understanding of
EFS, all these files should be enrypted with the same private key.
 
It sounds like differ EFS private keys are being used to encrypt the files
which means you may have more that one certificate in your user certificate
store that can encrypt EFS files which you can view via the mmc snapin for
certificates for user. Use the support tool efsinfo to examine the
thumbprints of the certificates used to encrypt the files to see if they are
the same for all files or not. --- Steve

http://support.microsoft.com/default.aspx?scid=kb;en-us;243026&sd=tech ---
using efsinfo
 
Thanks for the tip, Steven. efsinfo does not show there is any
different private key. However by working through your suggestions, I
noticed that there is a certificate from a third PC in my desktop PC's
certificate store. I imported that certificate into my laptop PC, and
the problem went away. In summary, I still cannot piece together what
exactly went wrong, but at least my immediate symptom disappeared. I am
happy.

I will have the efsinfo tool standby should the symptom resurface.
 
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