Resolve Corrupted Cache Problem

via 

PurgeIE - Purge Cache, Cookies and Tracks for Internet Explorer

Windows 8 Note  -  PurgeIE, PurgeIE Pro and PurgeFox were designed to work with Microsoft's Internet Explorer. Prior to Windows 8, Internet Explorer utilized files named Index.dat for indexing the Cache, Cookies and History information.

Beginning with Windows 8, Index.dat files are not used. The indexing functions are implemented within a Microsoft database system.


This page is an extension of the PurgeIE FAQ question -

         How do I resolve the problem with "Corrupted Cache"?

Note - this page also applies to "PurgeIE Pro" and "PurgeFox"


First you need to determine the location of the Cache error.  This document assumes that you are seeing the "Error in URL" indicator within your purge report.

The "Error in URL" messages in the listing indicate that the Index.dat file in one of the Internet Explorer folders (directories) has been corrupted.  The message includes a one-letter code that indicates the type of URL involved.

  "C" indicates the Cookie folder.
  "N" and "S" indicate the Cache folder.
  "V" indicates a "Visited URL" entry.

The "Visited URL" entries are retained in an Index.dat file in the History folder.  Internet Explorer uses these entries for its AutoComplete function and for controlling the highlighting of imbedded links on the Web pages.

PurgeIE's processing of the entries found URLs that the system's Delete function did not find else refused to delete.  This "should not occur".  However, it can and will occur if an Index.dat file becomes corrupted.

The Index.dat files can become corrupted when one fails to properly shut down windows or when the power fails or by some system lockups.  Upon corruption, some of the URLs are isolated and can't be properly referenced.  The "Error in URL" message indicates a URL that PurgeIE can display but can't delete due to corruption.  PurgeIE uses only standard Windows system functions for processing the Index.dat files.

PurgeIE contains an Emergency function for deleting the primary Index.dat files or the complete IE folders so as to simplify handling of corrupted files.  One could delete these folders via booting to DOS for Win-95/98 or for NT (without NTFS).  I have included the function as I found it to be quite difficult to describe a foolproof manual process for some newcomers to the PC.


Recommendations follow:

For the Cookie folder - If you wish to try retaining your Cookies, you could try deleting only the Index.dat file within the Cookies folder.  IE-5 and IE-6 will then build a new Cookie Index.dat file from the Cookie text files.  

NOTE - Apparently, IE-7 does not populate the new Index.dat file from the Cookie text files.

For the Cache folder - You may as well delete the complete folder.  Deleting only the Index.dat file would simply orphan the Cache data files as they would not be accessed by IE.

For the "Visited URLs" - You should try deleting only the Index.dat file within the History folder.  This retains the daily History information.

Please note that in some situations, errors can occur in a Cookie data file or in Cache data file and that deletion of the complete folder becomes necessary.


Emergency function for deleting "Corrupted Cache"

The Emergency function is accessed by pressing the "Tools" menu option and selecting "Purge I.E. Folders at next Reboot".  As indicated by its title, you will have to reboot to complete the process.  You can select to purge either, or all, of the three primary IE folders.  Also, you have the option to only delete the Index.dat files in these folders.


The following example assumes that only the Index.dat file in the 'History' folder (for "Visited URLs") is to be deleted.

    Start "PurgeIE"
    Click the "Tools" menu option
    Select "Purge I.E. Folders at next Reboot"
    Select "Index.dat only" next to the "History Folder" checkbox
    Press the "OK" button

The specified Index.dat (or folder) will be deleted at the next system boot (startup).


There is additional information addressed in the answers for the following other questions:

'What does the "Error in URL" phrase mean in the displayed messages?'
'What do the codes in the Type field mean?'
'What is meant by "Corrupted Cache"?'.


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Revised: August 23, 2015