I'm sorry to the OP who wasn't paying attention to the changes that have been made over the last several years. However, at this point, don't have too much sympathy. I don't mean to be harsh.

UA's mileage expiry policy changed, what, 4 - 5 years ago now. So it's not like this should be new. It's also pretty much the member's responsibility to keep track of this kind of stuff. Yes, its nice when places send reminders like this, but it often doesn't happen. If the miles (or whatever) are important, its probably a good idea to check in once in a while to make sure you know the rules, and do what you need to do to meet them.

While UA may not have emailed the OP, the info. shouldn't have been hard to find, It's right next to the mileage balance on the top of one's account page - in pretty decent size font, too. I also don't blame UA for having expired miles - MP is a loyalty program, and can sympathize with the fact that they don't see those with 18 months of inactivity as loyal. Especially when its so cheap and easy, and doesn't require a flight - to put miles in if you need them - enroll in MP Dining and get a few miles when gong to the restaurant you go to every month or two...buy something through the UA portal, which has a place, probably many, where you normally shop and buy stuff from. Even if not, easy enough to find a song on iTunes for ~$1.00, which would add the 1 or 2 miles to re-extend everything.

I have an Aeroplan account from when I grew up in Canada - I've had a couple of redemptions in the last 10 years, but basically, don't use the account anymore. It's harder to keep it alive than with UA, but I still manage to pop into an Esso station once a year when I'm in Toronto, spend $3 on whatever I need (or don't even need) from there, and garner a mile to keep it active. It really isn't that difficult.