Hi,
If only your regular Mac User account that is effected with the issue then you are right that it is unlikely that Restore is going to sort this out.
Finding the solution is going to take time.
This next process is time consuming more than anything else.
Create a new Folder on the Desktop and open it.
Use the Finder > File Menu to open a another "new window".
In the second one use the Go Menu > Go to folder items and enter ~/Library/Preferences in to the Dialogue Box.
Now, off the .plists in this folder we are only concerned with the ones that start com.apple.....
Move 1/2 (as in A to M in the next word in the names - com.apple.AddressBook..... is likely to be near the top of those) to the Desktop folder you created.
Next Shut Down the Mac and restart.
Many of the .plists involved in the move are likely to be recreated and in some cases App will be missing info. (which is why they are saved on the Desktop)
If the issue is resolved at this point we will know the culprit is in the moved half.
Go to the Desktop Folder and take half of those (A - F say) and move them back to the ~/Library/Preferences Folder and restart the computer (you are most likely going to have to agree to replace the .plist in the ~/Library/Preference folder with the ones you are moving back).
If the issue remains resolved put the next half back (G to I or J)
Restart the computer.
You should always have a gap between the last letter of the group moved back and the com.apple.n item that is first in the original half left behind )for Me that is com.apple.NetAuthAgent.plist)
At some point the issue with the Quick Look function is likely to be seen again.
When this happens move half of the last amount you moved back to the Desktop folder (so if it was between the G and J items then move I and J back to the Desktop folder)
If the issue is not resolved at the first move then you will have to swap the two first halfs and then work backwards from Z. (My Last .plist of the com.apple. ones is com.apple.xpc.activity2.plist so not actually Z).
To Summarise.
It is likely to be a .plist that is at fault.
The ones for Apple Apps start com.apple so you only have to concentrate on these.
The easiest way if to move half out of the way and with so many you can do this alphabetically by the third word in the name.
If the issue is resolved put half the moved ones (in the Desktop folder) back in ~/Library/Preferences.
If the issue is not resolved at the first split then swap the two halfs so that N to Z are the one in the Desktop folder.
In adding back the next half each time aim to leave a distinct gap in the names (so if A to M was the set in the Desktop folder move back A to G so that there is an obvious gap between the last g item and the original left behind N item. If N-Z ends up being the first ones on the Desktop then move back N to P)
You will need to Restart after each move.
Eventually you should come down to 10 or so .plist that it is likely to be. The name of the .plists involved may make it more clear at this point.
You may also be able to leave some out from a reducing number of .plists to say time.
AS I said this is long winded and time consuming.
Some .plist will contain license for certain apps so it is not suitable to just ditch the lot and start again.
8:29 pm Monday; October 27, 2014
iMac 2.5Ghz i5 2011 (Mavericks 10.9)
G4/1GhzDual MDD (Leopard 10.5.8)
MacBookPro 2Gb (Snow Leopard 10.6.8)
Mac OS X (10.6.8),
Couple of iPhones and an iPad
