Why am I seeing these weird characters in the popup that asks for my password when I try to update Adobe Flash on my Mac? I'm running OS X Yosemite on a Macbook Pro. I recently had an update for adobe flash but when the password prompt pops up to continue the installation of the update it looks like this:


What's going on here? I don't have any issues with characters missing anywhere else on my laptop. It's only when it asks me to enter my password for any system changes. Is this some kind of malware or just a system font issue?
Your system fonts got corrupted. 

Stop/Ignore the flash update and start in safe mode.

Now use the Font Book app in the applications folder.

Use the File- restore standard fonts.