Most of the icons images in my applications folder have changed to a picture of a blank page with a ruler, pencil and pen on it - also a couple of app icons in my dock have changed to this same picture. Any ideas what's happening?
iMac with Retina 5K display, macOS High Sierra (10.13.2)
Go step by step and test.
1. Try starting up in Safe Mode.
Start up in Safe Mode. https://support.apple.com/en-us/HT201262
Once in Safe Mode, click the “Restart” button at the bottom.
2. Reset NVRAM/PRAM couple of times. http://support.apple.com/kb/PH18761
3. Reinstall macOS from macOS Recovery. https://support.apple.com/en-us/HT204904
Thanks for the reply Dominic - I'm a 70 year old new to Macs so I will have to carefully try your suggestions.
The most of the icons images in my applications folder have changed.
