Hi I have Lightroom 6 for a few years now and for some reason since yesterday I cannot open it. I've never had this problem before as I use it almost every day. as you can see in the photo it wants to open but won't
When was the last time you restarted your computer? That might resolve the issue. If not then you might consider resetting the preferences. Here is a link on how to do that. It refers to Lightroom Classic, but it is the same for Lightroom 6.