We are having a problem since upgrading a few of our Dell sx260 systems to
the 4.91 sp1 client, when users lock their workstation and then try to
unlock they receive an error message. The message reads:

An unexpected error occurred while attempting to unlock the workstation.

Try to unlock the workstation again, or select a different credential type
for unlock.

Error -1497 (0xFFFFFA27)

I am able to unlock it using a local windows administrator account but that
causes the user to be logged out and they lose whatever they were working
on. Also I have noticed that after I do that until the workstation is
rebooted I am unable to remote into the workstation.

I have applied 4.91 Login files update and the 4.91 connectivity update and
still have the problem. Any ideas what I should try next would be