Unable to open backup device, operating system error 5

There are ab two servers, the format of the hard disk is nfts, the database of a server after the transfer to B server, and then restore the database on the B server when the backup file is not found, in fact, the file exists, such as:

If you enter the backup file directly, you will be prompted with the following conditions:

This problem occurs because of disk access permissions, and if you do not want to handle that much, there is one of the most stupid ways:

First in the B server randomly set up an empty database, assuming the name of test, and then back up the database to a directory, assuming that D:\DBBackup\1.bak, and then copy the backup files from the above to this directory, and then restore the backup files through the database appears.

Unable to open backup device, operating system error 5