I am also having this problem, may times during the day. It is particularly annoying when I get a phone call and really need to take notes of what I'm being told on the call and cannot access EN. Today I actually fired up MS Word (!) of all things to take notes that I could later paste into EN when EN decided to respond again. Amazingly Word was faster to use than EN. That's like saying Amtrak was faster than your airplane. Yikes. One theory I have is that this seems to always occur while the Outlook icon in the taskbar shows Outlook is syncing messages. Given EN's painful dependency on IE I would not be surprised if it also has some unnecessary reliance on an Outlook/MAPI API that cannot return until Outlook is responsive. Also, the last time it happened I looked at the activity log and it shows: 15:51:08 [23748] 100% * sent: 1.5KB, received: 366B15:51:08 [23748] 100% Connecting to www.evernote.com/edam/note/s115:51:08 [23748] 100% Session terminated normally, elapsed time: 0s15:51:08 [13984] Client synchronization finished, status: complete15:51:08 [13984] * 1 item sent 15:51:08 [13984] * elapsed time: 3m 48sSo - a sync that lasted 3:48 minutes! To sync 1 note that's 1.5KB! That shows 2 things: 1. The UI is still freezing during syncs. WHY? Get a book on multi-threading, guys! 2. Something can cause a 1k sync to last 3 minutes! Why? Again, I suspect an errant MAPI/Outlook call that is not multithreaded. I'm on Win 7, EN Win 5.2.1.3108, Outlook 10, very fast internet connection (during the middle of the 3+ minute freeze my resource monitor showed NO network activity).