I deleted the offending security update several times (it's like a bad penny in the cash drawer; it just keeps coming back) and that fixed the problem each time.
KB921398 haas finally ceased to re-install itself BUT I am now experiencing the same failure/inability to open zipped files on my Desktop.
Is there a new security install that's causing the same problem? Or something else someone's already figured out? Everything else appears to be working fine.
If you feel comfortable using the registry then try this...
My Documents fix
Drill down to the key:
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet
Settings\Zones\0]
Create a new DWORD "1806" with a value of 0
Zipped files fix
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet
Settings\Zones\1]
Create a new DWORD "1806" with a value of 0
Exemption Notice: Your on your own if you try the above. I will in not be respnonsible for any problem that you encounter for trying the above.
Please note: This works with XP SP1, should work with SP2.
EDIT** No worries for Vista users as this is for XP only.
Can the same zips be unzipped by the same program when not doing it via right-click menus off the Desktop? Seems odd that some are okay but others not, unless something is different with he zips themselves.