Resolving Windows Update Error Code 80071a91

Scenario:
Windows 7 Ultimate, security update KB2436673 failed with error code 80071a91.

Solution:
Found here: http://social.technet.microsoft.com/Forums/en-US/itprovistasetup/thread/2457b70d-d1d0-4049-ad8c-f769d3fb6578/, entry by vivekyadav75

Hi Friends,

Please check TxR folder in (c:\windows\system32\config).

If it is not there create it and issue will be resolved.

If not follow following commands.

1. Bring up an elevated (Administrator) command prompt

2. Execute the following commands sequentially:

a. fsutil resource setautoreset true c:\

b. cd %windir%\system32\config\txr 

c. attrib -r -s -h *

d. del *

3.Type: Cd c:\windows\System32\SMI\Store\Machine

Type: Attrib –a –h –s *.TM*

Type: Del *.TM*

Issue will get fixed.

Thanks and regards, 

Vivek

Resolving "The media is write protected" error for external hard drives in Windows 7

Scenario:
- PC running Windows 7 Ultimate, 64 bit.
- External USB drive Western Digital WD10000HIU
- Error: "The media is write protected" when trying to perform a 'write' (e.g. create a new folder/file, rename file, delete or otherwise modify the file).

Solution:
(Originally mentioned with thanks here: http://www.daniweb.com/forums/thread137013.html, by user 'Paddy')

1.) Launch 'regedit'
2.) Navigate to HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\StorageDevicePolicies\WriteProtect
    2.1) If the key 'StorageDevicePolicies' doesn't exist, create it
    2.2) Then create a new DWORD key under 'StorageDevicePolicies' called WriteProtect
3.) Modify value for 'WriteProtect' to 0, i.e. to turn off write protection.
4.) Reboot computer.
5.) Confirm resolution.

This worked for me.