Finder won't show icon previews of my items.

Hey everyone - SOLUTION FOUND!

It was in another thread with this same issue - an answer by berlindavedsg

Nov 27, 2020 10:47 PM in response to jrlombard

I think I solved this. It was a problem in Dropbox syncing and not my other files. Switch your Sync preferences in your Dropbox preferences from online to local. Then the files will be available in Preview. You will see the green checkmark beside each file in your Finder that will confirm the process has completed.

I found this procedure that someone has posted, I did what was stated and now I can see preview of my NEF files which are 50mb each,

Open to the Preferences folder of your home directory, or from Finder>Go>Go to Folder, copy & paste:

~/Library/Preferences/com.apple.finder.plist

Delete the com.apple.finder.plist

From the Finder icon on the Dock, hold the control option key and click the Finder icon>select Relaunch.

If you're suing Drop box, try this:

Go to /Users/youruser/Library/QuickLook/

and if there is a DropBoxQL.qlgenerator move it to the trash.

Then wait 5-10 seconds, and open a folder where previews weren't working.

Boot into Safe Mode by booting with the Shift key held down and check there to see if the problem persists.  Reboot normally and test again.

NOTE: Safe Mode boot can take up to 10 minutes as it's doing the following; 

• Verifies your startup disk and attempts to repair directory issues, if needed

• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)

• Prevents Startup Items and Login Items from opening automatically

• Disables user-installed fonts 

• Deletes font caches, kernel cache, and other system cache files

Also have you installed or run any "cleaning", "optimizing", "speed-up" or anti-virus apps on your Mac?

We can't do anything about it because we're all users like yourself. Apple engineers do not frequent these forums.

All we can do is suggest various procedures that might correct whatever wrong with your setup.

Boot into Safe Mode by booting with the Shift key held down and check there to see if the problem persists.  Reboot normally and test again.

NOTE: Safe Mode boot can take up to 10 minutes as it's doing the following; 

• Verifies your startup disk and attempts to repair directory issues, if needed

• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)

• Prevents Startup Items and Login Items from opening automatically

• Disables user-installed fonts 

• Deletes font caches, kernel cache, and other system cache files

Any improvement. If not download and run Etrecheck. Etrecheck is a diagnostic tool that was developed by one of the most respected users here in the ASC and recommended by Apple Support  to provide a snapshot of the system and help identify the more obvious culprits that can adversely affect a Mac's performance.

Copy the report

and use the Additional Text button to include the report in your reply.

IMPORTANT:

Before running Etrecheck assign Full Disk Access to Etrecheck in the Etrecheck's Privacy preference pane so that it can get additional information from the Console and log files for the report:

Also click and read the About info to further permit full disk access.

Then we can examine the report and see if we can determine what might be causing the problem.

If you want to tell Apple about your problem either use the phone no. at the bottom of this page or do it at Feedback - macOS - Apple.  

Get back to us on this two procedures and we'll start looking into what might be the problem.

Look closely!

All these have a little cloud badge.

YOU (perhaps unwittingly) confirmed when asked if you wanted to have "Documents and Desktop in iCloud".

These are in the cloud, and that is why you are not seeing the previews until you open them.

Have you installed or run any "cleaning", "optimizing", "speed-up" or anti-virus apps on your Mac?

Boot into Safe Mode according to Start up your Mac in safe mode - Apple Support and test to see if the problem persists. Reboot normally and test again.

NOTE: Safe Mode boot can take up to nearly twice as long as a normal boot as it's doing the following; 

• Verifies your startup disk and attempts to repair directory issues, if needed

• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)

• Prevents Startup Items and Login Items from opening automatically

• Disables user-installed fonts 

• Deletes font caches, kernel cache, and other system cache files

Hello B_Lars ,

Do you have the same issue if you use a different user account? You can create a new Admin account to test this behavior. Set up users, guests, and groups on Mac

If you experience this in a different user, let's start up your Mac in safe mode as it prevernts your Mac from loading certain software. Starting in safe mode will take a little longer than normal, because it verifies and repairs the directory, cleans caches, and loads only Apple-critical items. You can see How to use safe mode on your Mac.

Take care.

What do you have in your Photoshop preferences for Saving Files. This screenshot is from Photoshop Elements but Photoshop should have something equivalent:

If all else fails give this a try: boot into Safe Mode according to Start up your Mac in safe mode - Apple Support and see if the problem persists. Reboot normally and check again.

NOTE: Safe Mode boot can take up to 10 minutes as it's doing the following; 

• Verifies your startup disk and attempts to repair directory issues, if needed

• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)

• Prevents Startup Items and Login Items from opening automatically

• Disables user-installed fonts 

• Deletes font caches, kernel cache, and other system cache files

The problem is fixed in the latest update for Big Sur 11.5.2.

I never had a problem with thumbnails with Big Sur so it must be something associated with each user's system setup that is causing the problem. Big Sur is extremely stable and fast.

Have you installed or run any "cleaning", "optimizing", "speed-up" or anti-virus apps on your Mac? If you have then you should uninstall all of them according to the developer's instructions before updating/upgrading the system.

This may be crazy stupid!

changing the icon size with the slider in the finder window made it preview all the files in the window for me.

Im experiencing that all cloud files have lost their ability to show an icon preview (thumbnail). Im wondering if that is what everyone else is experiencing too but didnt mention it was only on cloud files? There is definitely something happening with icon previews - its unique to Big Sur. The above solution doesnt fully work for clouds files, it just moves the files local in order to restore the preview. Before Big Sur, all cloud (non-local) files had an icon preview(of the content). You could not perform a full quick view, but you could see a small thumb which was good enough to figure out what the content was. Now, they all have a generic 100% useless file-type icon.

This is a super frustrating issue. The problem seems to be with Dropbox folders not showing image thumbnails. Dropbox doesn't seem to be rushing to solve this problem as the same bug is described and no solutions are offered by them either.

I have the same issue and am use design files just like everyone else. I HAVE FOUND A POTENTIAL WORKABLE FIX if you use iCloud that is. It's not ideal but I mean it is better than everything else that people have said on here. Just go to iCloud.com and sign in and go to your iCloud Drive. The previews will be there on the web browser. Obviously this is not ideal and shame on Apple for having this problem go on this long. I HOPE THIS HELPS SOME OF YOU!