When the Encrypting File System (EFS) feature is disabled, such as by Group Policy, retrieving the MPIO configuration by using the mpclaim command together with the -v option causes an "Access Denied" error and doesn’t show the configuration.
Note MPIO represents Microsoft Multipath I/O.
This issue occurs because mpclaim always tries to write the configuration to an encrypted file.
Note After you install this update, mpclaim -v config.txt will continue to try to write to an encrypted file and won't work correctly when EFS is disabled. You should use the -n flag, mpclaim -v config.txt -n, which will write to a file that's not encrypted and succeed whether the EFS feature is disabled or not.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
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