It started randomly (haven’t made major changes in the last few days), so I assumed it was something corrupted. The only hint was that after Safari, Mail, iTunes or Adium crashed, PubSubAgent would use 100% CPU time. So, I fire up Instruments and look at the trace for PubSubAgent. It seems to be calling CFHTTPCookieStorageFlushCookieStores many times, which is odd, because a quick Google doesn’t return anything useful about this system call, obviously related to CFHTTP.

Fast forward 4 hours later when I’ve cleared caches, nuked my Safari config, tried removing PubSubAgent (which just made it worse). The fix? Removing ~/Library/Cookies/Cookies.plist. Oddly enough, it has a companion – ~/Library/Cookies/Cookies.plist – corrupt.

So, just a recap; somewhere the system knew my Cookies file was corrupted. But instead of spitting this out to the Console, throwing a Dialog, or ANY form of useful information, I had to trudge through my Library looking for something which could be causing the problem, and manually removing it. It was by chance that I noticed the Cookies folder, which is strangely not in the Safari folder where one would normally expect it.

And just to make matters worse; Safari’s “Reset Safari” did nothing to solve the problem. That’s right, checking the “Remove all cookies” checkbox did NOT remove the cookies!

Good user interaction FTW!