1) make sure you have latest build v0.8.54.0-unk-beta
2) if you're getting stuck per se, go to the the path where the appdata is contained. in my case it's C:\Users\abuchanan\AppData\Roaming\MemoryCoin so yours will most likely be C:\Users\[WINDOWS_USERNAME]\AppData\Roaming\MemoryCoin
3) Go and delete everything in there except wallet.dat and peers.dat
4) start up the memorycoin.exe again and let it sync back up from day 0 to now.
5) should be fine after this, if not addnodes...add more nodes...oh an keep adding nodes wait a bit and you should be okay.
Yes, this is the right solution. Already on www.MemoryCoin.info, see "does't sync after update?"
Everybody, please follow these instructions.