From gsak 201 :
Don’t know your Owner ID#? You can easily locate it using one of the following approaches:
1) If you have placed (hidden) caches: Go to the geocaching.com page for a cache you own and download the GPX file for that cache. Load the GPX file into your GSAK database. Add the “Owner ID” column to your GSAK view (see “Adding and Removing Columns”, above). Locate the cache you own in the GSAK Grid View and copy down the number from the “Owner ID” column.
2) If you have found caches: Go the geocaching.com page of a cache you recently found and download the GPX file for that cache. Open the GPX file with any text editor (e.g. Notepad, Wordpad, Microsoft Word, Word Perfect). Search (Edit>Find in most text editors) for the Geocaching.com name under which you logged the cache. This should take you to a line that looks like this: <groundspeak:finder id="123456">Geocacher</groundspeak:finder>. Your Owner ID# is the number right after “groundspeak:finder id=”.
3) If you don’t own any caches and haven’t found any caches: Log into geocaching.com and click on “Forums” in the menu on the left side of the page. Scroll down and click “Enter the Groundspeak Forums”. Click on the “Getting Started” forum, then click on the “Testing, Testing…Test Posting Area”. Click on the “Add Reply” button. Type anything in the entry box (e.g. Just testing) and then scroll down and click on the “Add Reply” button. Hover your cursor over (don’t click) your geocaching name in the upper left corner of the post you just added. Your OwnerID# will appear in the status bar at the bottom of your browser window, immediately after “showuser=”.
Once you have you Owner ID#, in GSAK, go to Tools>Options General tab, click on the circle in front of “Owner ID#” and enter your number in the white box, then click on the “OK” button to close that dialog box.
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