Error XXXX [AFTIndexFile.close] ‘\\ip address\BackupSpool\BackupSet\XXXX\RemoteTree.idx’ has not been opened
A Temporary Spooling Location has been set to a UNC path and the backup process does not have sufficient privileges to read/write to this path as the “Local System” user.
Often this is caused by a NAS device that requires authentication but since the “Local System” user does not exist on either the NAS user database or domain, access is denied.
Change the scheduler to run under an active domain account. On the machine to be backed up, go to [Control Panel]->[Administrative Tools]->[Services]. Look for the “Online Backup Scheduler” and alter the “Logon as” user FROM “Local System” to an administrator account, ensuring that the correct password is entered.