mount: nfs_server:nfs_share failed, reason given by server: unknown nfs status return value: 22
The problem is on the NFS Server side. We only had this problem
with the Microsoft Services For Unix NFS server.
Error 22 is given when the NFS server cannot create or use the ._nfs
folder in the root of the drive.
Check that the permissions are correct for this folder.
Special case
Check that the ._nfs folder has not been damaged. There was
one case where scandisk had converted a damaged ._nfs
folder to a zero-byte file.
In this case, stop the NFS server and run the following
commands in a DOS prompt:
cd \
attrib -r -h -s ._nfs
del ._nfs
and start the NFS server again.