why are image thumbnails not displaying in finder since updating to sequoia on my m1 MacBook pro

I doubt it is as much as Apple blocking third-party Quick Look code as the software may not have been recompiled to work with the current operating system and any Apple Frameworks that may have changed since the third-party plug-in was originally released. That is on the developer, not Apple.

I used to have a Markdown QL engine that was written several years ago that has not been updated or worked since macOS Big Sur because the original developer never stayed engaged with keeping it current.

In that Finder Window that you just provided a screenshot, press cmd+J to open the Show View Options panel. Is the Show icon preview selected, and if not, by selecting it do the generic icons change to their respective image?

When those PNGs were produced, was there an option to include an icon image that may have been overlooked?

Unfortunately not. I am updated and it's not fixed. In fact, I have new images that are solid white thumbnails now. If I click on the image and have the preview sidebar open it shows the image in the sidebar, but not the thumb.

Most of them with issues (if not all of them) are on the local HDD and not on external drives. So it's definitely a localized system issue.

In case this can be useful, below is AppleScript code to modify Show icon preview. The sample code can be edited and included in an Automator workflow (via the run AppleScript action) to process multiple folders.

- Pie Lover

Turn off icon preview

	tell application "Finder"
		
		open (choose folder)
		
		if (current view of front Finder window) is icon view then
			set (shows icon preview of icon view options of front Finder window) to false
		else if (current view of front Finder window) is list view or (current view of front Finder window) is flow view then
			set (shows icon preview of list view options of front Finder window) to false
		else if (current view of front Finder window) is column view then
			set (shows icon preview of column view options of front Finder window) to false
			set (shows icon of column view options of front Finder window) to false
		end if
		
		close front Finder window
		
	end tell

Turn on icon preview

	tell application "Finder"
		
		open (choose folder)
		
		if (current view of front Finder window) is icon view then
			set (shows icon preview of icon view options of front Finder window) to true
		else if (current view of front Finder window) is list view or (current view of front Finder window) is flow view then
			set (shows icon preview of list view options of front Finder window) to true
		else if (current view of front Finder window) is column view then
			set (shows icon preview of column view options of front Finder window) to true
			set (shows icon of column view options of front Finder window) to true
		end if
		
		close front Finder window
		
	end tell

philip@ wrote:

Solved (for me). Using Sequoia 15.3 this issue happened for the first time using Pages (thumbnail). Came here to find answer - nothing. My solution was to click on 'View' in the Finder menu, open 'Show View Options' and to adjust the thumbnail icon size 'slider'. Alternating from larger to smaller you can watch the generic thumbnail placeholder disappear / reappear as all thumbnails increase / decrease in size. I preferred them larger so left it at increased size and issue is gone. It also seemed to work by going back to original size after adjusting back and forth a few times but I wasn't paying too close attention.

That IS interesting! Yes, for me too, however the only way to get them all to show is at 80x80 sizing. If I increase more and more of the previews disappear. Very interesting development! Thanks! Now if I could just reset all my folders to be 80x80 instead of doing it manually, it'd be good until there's a fix.

Since I’m having the same problem, MacBook Pro m3 with 15.3.2 and last version of photoshop, are we sure it’s not adobe’s problem the icon preview issue? I can’t believe that apple keeps ignoring thousands of users without solving it

RyckyP wrote: "...Anyone know the process for inveigling (by flattery) Apple to fix the bug?"

Rycky ~ Use this form:

Feedback - macOS - Apple

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Make sure this View/Show View Option is set for each folder you're having problems with as shown below:

Can you me a bit more specific about what you are not seeing? Are we talking about the images that Finder displays for different parts of you Mac, like Applications, Documents, Desktop?

Clicking on one image and Get Info and see what "Open With" shows. On mine it shows Preview.

This is probably the only way. But I have a lot of files in different folders, and it's not very convenient to convert. I hoped there would be a fix in 15.0.1, but nothing has changed. Thanks anyway!

You mean they actually blocked third party thumbnail previews on purpose? What would be the rationale, if any? Safety?

This is usually a preferences updating problem.

Try deleting the com.apple.finder.plist and relaunching the the finder.