Using avast 2014 on XP/sp3, I have noticed that despite configuring IE8 to “Empty Temporary Internet Files folder when browser is closed”, in fact this is not occuring. This is a relatively recent behaviour. I definitely did not see it when using Microsoft Security Essentials as my AV. I have to clear my TIF (often 10-50 MBs) cache with CCleaner after closing IE8.
I have explored all the settings of avast, and cannot find an option to uncheck this “locking” of my TIF folder (currently located at C:\Documents and Settings\joseph\Local Settings\Temporary Internet Files).
Even if it did, I don’t know why it would only block deletion of the Internet Temp Files and not stop other deletions.
I haven’t experienced this on firefox, it is a very, very rare occasion when I use IE8 on this system.
I set the Internet Options to cleat the Temp Internet Files on browser closure. I have just done some browsing using IE8 and checked the Temp Internet Files folder and there was a little over 400KB of files. Closing the browser and doing a check of the Temp Internet Files folder the temp files were gone, some cookies remained and two .ico files.
Now I don’t have cookies deleted using the normal settings (Tools, Delete Browsing History), so that may explain why they weren’t removed. No idea why the .ico files wouldn’t be classed as Temp Internet Files.
After noticing this problem for weeks (months?) I can say it appears to be suddenly resolved, due to no particular changes made by me: not to avast nor to IE8 settings.
I have had the Avast Online Security Add-on disabled in IE8 ever since I installed Avast 2014 weeks ago.
Like you, my TIF files now only number in the 300-400 KB range (according to CCleaner), and the folder contains only protected (login) cookies and an icon or two.
Very curious that this glitch should suddenly disappear shortly after my original post.