Backup of Windows client exits with Status Code 1 and error "WRN - can't open file: xxx (WIN32 32: The process cannot access the file because it is being used by another process. )"

Problem

Backups of Windows clients are completing with Status Code 1 when some files are in use by another process.

Error Message

Activity monitor detailed status shows:

08/19/2011 12:02:21 - positioning GCS035 to file 61
08/19/2011 12:02:35 - positioned GCS035; position time: 0:00:14
08/19/2011 12:02:35 - begin writing
08/19/2011 12:04:23 - Warning bpbrm (pid=14902) from client client1: WRN - can't open file: C:\System Volume Information\Syscache.hve (WIN32 32: The process cannot access the file because it is being used by another process. )
08/19/2011 12:04:23 - Warning bpbrm (pid=14902) from client client1: WRN - can't open file: C:\System Volume Information\Syscache.hve.LOG1 (WIN32 32: The process cannot access the file because it is being used by another process. )
08/19/2011 12:04:23 - Warning bpbrm (pid=14902) from client client1: WRN - can't open file: C:\System Volume Information\Syscache.hve.LOG2 (WIN32 32: The process cannot access the file because it is being used by another process. )
08/19/2011 12:05:18 - Warning bpbrm (pid=14902) from client client1: WRN - can't open file:C:\Windows\ServiceProfiles\LocalService\AppData\Local\lastalive0.dat (WIN32 32: The process cannot access the file because it is being used byanother process. )
08/19/2011 12:05:18 - Warning bpbrm (pid=14902) from clientclient1: WRN - can't open file:C:\Windows\ServiceProfiles\LocalService\AppData\Local\lastalive1.dat (WIN32 32: The process cannot access the file because it is being used by
another process. )
08/19/2011 12:05:18 - Warning bpbrm (pid=14902) from client client1: WRN - can't open file:C:\Windows\ServiceProfiles\LocalService\NTUSER.DAT.LOG1 (WIN32 32: The process cannot access the file because it is being used by another
process. )
08/19/2011 12:05:18 - Warning bpbrm (pid=14902) from client client1: WRN - can't open file:C:\Windows\ServiceProfiles\LocalService\NTUSER.DAT.LOG2 (WIN32 32: The process cannot access the file because it is being used by another
process. )
08/19/2011 12:05:18 - Warning bpbrm (pid=14902) from client client1: WRN - can't open file:C:\Windows\ServiceProfiles\NetworkService\NTUSER.DAT.LOG1 (WIN32 32: The process cannot access the file because it is being used by another
process. )

Cause

The policy's Type had been incorrectly set to Standard, which is for Unix/Linux clients.

Solution

Changing the Policy Type to MS-Windows resolves the issue.