Debugging IFilters in MOSS/WSS.

The steps we use to debug searchfilters with MOSS/ WSS are listed below:

1.     Disable filter host termination, add Assert to suspend filter host when it starts:

MOSS  [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office Server\12.0\Search\Global\Gathering Manager]

WSS  [HKEY_LOCAL_MACHINE\SOFTWARE \Microsoft\Shared Tools\Web Server Extensions\12.0\Search\Global\Gathering Manager]


2.     Restart the OSearch service.

3.     MOSS:  Start a full/incremental crawl

WSS:  Touch the file of interest by opening it and modifying it slightly, and wait a few minutes.

4.     When you see the filter host assert, attach a debugger to mssdmn.exe.

5.     In the debugger, sxe ld <filter>.dll  (or you can do this via Image File Execution Options)

6.     Set break points in your IFilter dll.

7.     Set symbols for your IFilter.

8.     Wait for Break Point to hit.

9.     Start debugging.

Comments (6)

  1. Jason Medero says:

    Hi Deb,

    I was wondering if there is an official documentation on creating custom Ifilters for MOSS/WSSV3?  Has anything changed from custom developed IFILTERS for SPS 2003?  I have found documentation on MSDN for IFILTERS and SPS 2003 but nothing about MOSS 2007/WSS V3..  Any guidance would be greatly appreciated!


  2. Deb Haldar says:

    Hi Jason,

    We don’t have an official documentation yet for MOSS/WSSV3. However, the only difference is in the way the filter is registered with MOSS/WSSV3. Other than that, there is no other difference. Actually, filters which were functional on SPS2003 still works on MOSS 2007 once the proper registry keys are set.Please refer to the Filter registration guidelines in the blog for MOSS/WSS.



    P.S. 1. If you’re writing a filter right now, we recommend loading via IPersistStream as future MS products might deprecate loading via IPersistFile or IPersistStorage.

  3. Jason Medero says:

    Great thanks Deb you have been a great help!

  4. lele says:

    that debugger I must use that one of visual studio 2005 or windows debugger tools?


  5. Deb Haldar says:

    It’s Windbg which belong to windows debugger tools.



  6. Lele says:

    You could write me step by step like configure windbg(symbols , source ecc…)