Purge all Google Chrome user data on a MacPosted in Applications and OSX -
In Google Chrome you can easily purge browsing data including cookies, history, etc using the application preferences. But there are still a bunch of files that it doesn't touch. I was having some weird issues with my SilverStripe installs (I won't go into that here) which didn't happen when using incognito mode but did under normal browsing. Deleting all browsing data made no difference so I needed to really poke under the hood to delete all data.
Purge all user data
This is method to purge data from within Chrome using the current version as at August 24th 2011 on a Mac. This should purge everything that most users would need it to purge.
Go to the preferences menu by either using the Command+, keyboard shortcut or clicking the wrench icon top right in the browser and selecting the preferences option.
Then select "Under the Hood" and click the "Clear Browsing Data" option. Select all options and the click the "Clear Browsing Data" button.
Google Chrome's Application Support Files
The issue I had did not appear to be related to browsing/download history, cache, cookies etc so doing the above didn't fix it. Instead I needed to delete/rename Chrome's application support files - the solution below worked for my particular issue.
On a Mac there's a directory called "Library" under your home directory, but as far as I can tell this doesn't show up in Finder (at least not on Lion) although I had a feeling there should be a Library folder there. But you can still navigate your way there in Finder.
The folder we want to get to is ~/Library/Application Support/Google/ so select "Go" then "Go to folder" from Finder's menu and copy and paste ~/Library/Application Support/Google/ into it. Then click "Go".
In that folder is a folder named "Chrome" which is where the user support files are. Make sure you've shut down Chrome and then either move the folder to the trash or rename it to something like "Chrome.backup" and then start Chrome up again.