Curious "Access Is Denied" Error When Synchronising Offline Folders

I have a curious error when a user synchronises offline folders.

All of our users "My Documents" folders are held on a server via group
policy. Workstations do not use synchronised offline folders, they are
simply diverted to the server for their "My Documents"

Laptops however (for obvious reasons) use synchronised offline folders for
their My Documents. They are also stored on the server, but synchronisation
occurs to hold a local copy for when they are out of the office.

This all works a treat for about 120 users (50 laptops). One user however
has suddenly reported a load of errors when synchronising. He has hundreds
of files, and the vast majority are fine, but there are about a dozen
spreadsheets that report an error "Unable to make expenses_dec2009.xls
available offline on \\data\staffmydocs\john_s\My Documents\expenses Access
is denied".

I don't understand this as it is simply an expenses spreadsheet similar to
others that have not had a problem, and also that was created by this user.
I have checked the security attributes for the file and it is correct for
the user also.

Open up the Event log from the laptop that is experiencing the issue. See
if you are getting any specific errors related to the user. Also verify
that the user is really logging in and he isn't using cached credentials.

I actually logged in as this user on my laptop and got the same
sync issues. Sorry, I should have made this clear.

Try netdiag on the laptop to see if you have connectivity issues.

netdiag.exe /v

Forgive me Paul, but unless I'm missing something this is probably
pointless.

Sales person has the issue, and sends me a screenshot of all the files that
can't sync. He has no other issues on the network, and network activity is
pretty much choc a bloc with Outlook (Exchange 2003), SalesLogix and Sage
etc.

I then log in as him on my laptop and get the same issues with exactly the
same files. It is only with these specific files that the issue relates to,
and these files are within folders that contain other files (spreadsheets)
that sync perfectly. The files that fail are perfectly readable, and I was
able to copy one to the desktop, delete it from within "My Documents" (the
folder that is being synced) and then copy the file back in again.

The part of the error that states "Access is denied" makes no sense as the
file is readable, deleteable, moveable and sits in a folder where other
files can be synced perfectly well. He has stacks of drive space on his
local machine and so do I on mine. I had even considered maybe there was
something in the formatting of the spreadsheet that linked to something else
that could not be synced accross, but one of the files in question has
simply been created from a template, and there are several other files that
have been created in the same way that are fine.

Ok, I guess I didn't have a clear understanding of the issue. I still would
run the test but I think you are correct.

Does anyone else have an idea about this. It is still on going and there are
a couple of other users now with the same issue!

First and foremost, make sure that the NTFS permissons on the network share
are correct. Let's just make sure that is in place (this is not the
solution...just part of it).

Next, check to see if the Offline Files are subject to be encrypted. I am
going to bet that they are. This is located in the Computer Configuration |
Administrative Templates | Network / Offline Files and the policy is
"Encrypt the offline files cache". Going to be that this is indeed enabled.

The next thing that you need to do is to take a look at the certificate that
is being used for EFS. I am going to bet that it has expired. I might
suggest that the errors that you are seeing started when the certificate
expired. You will find this setting in the Computer Configuration | Windows
Settings | Security Settings | Public Key Policies | Encrypting File System.

Please note that you can not replace this Certificate. You would either
have to add a new one -OR- you can disable the encryption on the offline
files cache.

Does this help?

It certainly does help Cary, and I feel I am getting somewhere. Thanks very
much. :-)
Findings are:

NTFS permissions are fine for the folders.

"Encrypt the offline files cache". is enabled.

there is nothing set in Encrypting File System.

I do remember now that I set laptops up with offline files for their My
Documents and encrypted to add protection if the laptop is lost. All fixed
workstations simply have their My Documents redirected to the server.

Can you tell me what my best way forward is?