I've recently been having issues with Discord. The desktop app would not load correctly and would eventually go to a gray screen/box that would not allow me to do anything. Long story short, I found this link to be helpful in solving the issues. Only took a few seconds..
Steps:
1. Go to "run" (Window key + R)
2. Type "%appdata%" and hit enter
3. Delete the "Discord" folder or the "Cache" folder inside Discord folder
4. Launch the Discord app
Steps:
1. Go to "run" (Window key + R)
2. Type "%appdata%" and hit enter
3. Delete the "Discord" folder or the "Cache" folder inside Discord folder
4. Launch the Discord app