I am rookie Exchange Admin. I inherited this setup from a sw developer and outsourcing company about a year ago. Often, email sits in the queue for an indefinite period of time and gives no notice of there being an error.
Most of the time, if I reboot the server, it will send the emails and/ or generate errors; sometimes, several days old. Currently, I reboot the server (2003 for small biz) nightly to try to force mail activity, but that is obviously treating a symptom. Force/ unfreeze tend to do nothing, so I am probably not using them correctly.
I have 1.5GB of space on my root drive, but the mailboxes sit on another drive with plenty of space. I have 4GB of memory. I do not know if internal ever gets delayed or not. What else can I check?