So, apologies if this was already posted. I've been getting VERY FRUSTRATED as I slowly watched the memory usage for htc mail creeping up and up. I was up to over 80 megs, and the performance of my incredible was notably getting worse. I was looking and looking, and although I found a lot of other people having problems with htc mail, I never found a solution to it other than a hard reset. So I deleted my hotmail account (left the gmail account alone). Instantly down to 15 megs. Reinstalled the account, reloaded my mail. Still only at 15 megs. So if you're getting the "low on memory" error, try removing all your email accounts except gmail, then re-adding them. Worked for me.