Ever since my transition to 10.10.5 Yosemite, quick look keeps corrupting the preview images every now and then. Sometimes is persists until reboot, other times it goes away after a while. The image files themselves are fine and open and display in any application.
Any ideas?
Example:
Best Answer
Create a guest Account
and test if the problem still persists. To activate the guest account use the following steps:
Repair disk permissions with disk utility
Sometimes files are corrupt and can be repair using the disk utility.
Insert the following path into the small window and hit Enter to open the location:
/Applications/Utilities/
Open Disk Utility and choose on the left panel your System drive.
Try to reset the quicklook cache
Open Terminal (you find it in the utilities folder - see location above), and type the following commands:
After this is done you need to move some files to your desktop.
Open the following path location and move the files marked bold to your Desktop. Click on the Finder Desktop and press Command + Shift + G and insert the following path in the window:
Move the following files to your Desktop:
com.apple.QuickLookDaemon.plist
com.apple.quicklook.ui.helper.plist
com.apple.quicklookconfig.plist
Restart and Test
Check for Hardware Issues
To see if there isn't a Hardware Problem restart your mac and press the D key during startup.