This bug is found in those Windows 7 and Server 2008 R2 systems which were upgraded to SP1 manually, i.e. you installed Windows 7 and Server 2008 R2 without SP1 first and then manually upgraded to your system to SP1 by running its installer.
If you are using a slipstream version of Windows 7 SP1 or Server 2008 R2 SP1, this bug will not occur in your system.
Official words from Microsoft:
After you install Windows 7 Service Pack 1 (SP1) or Windows Server 2008 R2 Service Pack 1 (SP1), binary files in some USB drivers are not updated. For example, the Usbport.sys, Usbehci.sys, and Winusb.sys binary files are not updated.
Information from our reader "Tito":
Of the several USB-related driver files updated by SP1, three files, usbport.sys, usbehci.sys, and winusb.sys (note: not all hardware configurations use winusb.sys, so it is normal for it to be missing) were only partially updated; i.e., the SP1 installer only updated the "repository" copies of these files, i.e., the copies found in WinSxS and DriverStore. The "active" copies, found in System32\Drivers, are not updated (this is a bug with the installer). People who did a new installation using an integrated ISO are not affected (both the "repository" and "active" copies are 7601) (so this only affects a 7600->7601 update), and other USB-related driver files seem to be unaffected (e.g., the SP1 installer updates both the "repository" and "active" copies of usbhub.sys).
Just download official Microsoft fix using following links:
Thanks to our reader "Tito" for sharing it...