I'm having the same type of issues... both on EN on Windows 10 and on my iPhone. So it's not limited to one platform for me. EN goes typically goes unresponsive for 30 to 60 seconds (sometimes more) at a time. I've tried running all of the cntrl-help repairs and turning off instant sync, but to no avail. I suppose I'll try reinstalling but other users haven't gotten results with this. I've been using Evernote for many years (since the early days of the product) and have had nothing like this issue until about the past month. Since there are so many users having this issue, I believe it's a product-related issue that shows up under certain conditions. Evernote needs to give this some attention and get it resolved. It's very frustrating to deal with and we need a fix.