Niku Said:
"Image disappears from screen when I try to copy it: I copy things from the screen all the time, text, pictures, images. etc., but sometimes when I try to make a copy, the image disappears before I can make. copy. In other words, the act of copying makes the image disappear.[...]"
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A Few Thoughts:
A. Reset your SMC and your NVRAM:
Sometimes changes are made to the system and then settings (i.e. for keyboard) become corrupted, technically. So, reset both on your Mac. See where if the keyboard works from there. It might take up to 3 tries ro successfully reset both.
B. Scan your Mac for Malware:
Use MalwareBytes for Mac --- This is software that searches for malware/adware. So, scan with it and then remove what is found. Once removed, uninstall MalwareBytes for Mac. Then restart the Mac.
Downloads:
- Malwarebytes Anti-Malware for Mac
- Malwarebytes Uninstaller
C. Single Out this User:
See what happens when you create a new Administrator User and login to it and perform the above. If it works, then it is something mid configured in your current user. So, move everything over to this new user, and then delete this user you are currently logged into.