I have used the 2X app for my business for the last 2 years, and must say it has been quite good and stable. I had the occasional issues, but most of those were related to my bad wireless connectivity. With this recent update I am a bit worried about 2X. I Recently updated this app on my non-Retina display Macbook Pro, I had read the other review about it not causing issues but decided anyways. To my relief I did not encounter the issues that other reported. Thinking that all was good I went ahead and updated my newer Macbook Pro WITH Retina display and everything has slowed to a glacial crawl. I’m not sure what happened in this version of the 2X app, but you need to fix it ASAP as I now have a completely unusable Macbook Pro Retina. If you have a Mac with a Retina display DO NOT UPDATE, it will break your ability to use the app. Such an obvious flaw should have been picked up by this company before allowing us to get it.