How can I test mapped network drives in the advanced disk test?

Due the way Windows User Account Control (UAC) works programs like PerformanceTest, that run as elevated administrator, are unable to access mapped network drives that were created by other users.

The suggested workaround is to edit/create the "EnableLinkedConnections" registry value at "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System" and set it to a value of 1.

There is more information available here.