Paul; the reason I'm polling is that I want to try to determine whether it's just me or whether it's a common problem. And no, I don't know anything you don't; I'm hoping that this process might help find a solution.
Jon; I have an 86GB hard drive with 30GBs free. And yes, my laptop is connected to my network via a wireless connection.
Until you suggested clearing the cache, and I went and read the help file, I didn't realize you could clear the cache without clearing the history; and it's very helpful to me to have 30 days of history available. So, now that I know you can clear the cache while leaving the history intact, I'll try changing the settings to automatically clear the cache upon closing, and see if that helps.
