mp4, m4v missing thumbnails OS Monterey

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Hotch3f Author

Level 1

10 points

mp4, m4v missing thumbnails OS Monterey

Since upgrading to Monterey my mp4, m4v files are missing their thumbnails.

I have many movies that i used Subler to add a cover photo and these all worked before and were visible in Big Sur

i have tried the removal of com.apple.finder.plist and forced finder to relunvh and this does not work.

Here lies the problem.

If i reboot the iMac the folders all show the thumbnails correctly, but if i leave the computer for a few hours and return and wake it from sleep the thumbnails are all gone.

if i transfer a mp4 from something like my GoPro the thumbnail does not even show the preview in the thumbnail. just a generic white thumbnail. But again if i reboot it is fixed, but once the computer is woken from sleep they are again gone!! This only happens after a few hours of sleep and not if i let it sleep and wake the mac after a few minutes.

Can anyone help

Posted on Nov 2, 2021 2:51 AM

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Answer 1

Top-ranking reply

Hotch3f Author

Level 1

10 points

Nov 4, 2021 1:14 AM in response to Hotch3f

After days of trying to sort this out i did a clean install of OS Monterey over the top of my exisiting OS. 24 hours later and everything seems to be fixed. woke the computer after a long sleep and all the thumbnails are still there!!!

There must have been a glitch in the Matrix.

Thanks to everyone that responded

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Answer 2

Jeff_W.

Community Specialist

Nov 3, 2021 6:34 AM in response to Hotch3f

Hello Hotch3f,

Thanks for reaching out in Apple Support Communities! We understand you're having trouble with your thumbnails since updating to Monterey. We're happy to assist you with this.

Let's start by testing in safe mode. This can help bypass software that can cause conflicts:

How to use safe mode on your Mac - Apple Support

Where are the files located on the Mac? For example, are they located in a folder or iTunes?

Does this occur in any other user accounts?

Does this occur on the files that you didn't use Subler with?

These details can help us isolate the cause of the issue.

Best regards.

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Answer 3

jdo_apple

Community Specialist

Nov 3, 2021 7:44 AM in response to Hotch3f

Hi Hotch3f,

Thanks for the update. We recommend ejecting and disconnecting the external drives and test to see if the same thing happens with the files on the Mac. If so, run disk utility on your hard drive: How to repair a Mac disk with Disk Utility

Next, connect the external drives back and run disk utility on them. If the issue persists, Contact Apple for support and service.

Have a wonderful day.

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Answer 4

Hotch3f Author

Level 1

10 points

Nov 30, 2021 7:41 AM in response to Hotch3f

So I have found a new solution and so far all the thumbnails are back and working.

The solution is to force-quit the QuickLookUlService in Activity Monitor

I did force quit all of these just to be safe and reloaded Finder and evrything returned instantly

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Answer 5

Hotch3f Author

Level 1

10 points

Nov 3, 2021 7:04 AM in response to Jeff_W.

When i boot into safe mode the thumbnails are restored. I knew this would happen as when i reboot my iMac the thumbnails return. The problem occurs after a few hours of sleep time on my iMac. The iMac is always on as it is the media library for all my Apple TV's.

The files are located in folders some on the iMac and some on external hard drives (both of which have the same problem)

I don't have any other user accounts on the computer as it is only myself that uses it

This occurs in files that i have not used Subler for ( like transfering mp4 from my GoPro)

also i have now noticed that is also affecting .jpg files and .nef files ( i am a photographer as well) these now do not show any previews.

The problem always fixes itself after a reboot but after several hours it goes back to no preview in the thumbnails

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Answer 6

NormanUK

Level 1

14 points

Nov 5, 2021 3:32 PM in response to Hotch3f

I am having the same problem on my iMac and have been searching for a solution for a few days now.

Like you, I also loaded a clean install over my existing one and for a few hours it looked as though I had solved the problem but soon the JPEG, PDF, MP3 and M4V previews were all missing again.

I have now deleted 3 seperate times the preference file com.apple.finder.plist from the library which was a suggested solution on some websites - but it doesn't help.

A shut down, re-boot and a re-set of the NVRAM worked once, but after an hour or so the preview icons reverted to generic icons again.

Interestingly, my MacBook Pro which I updated to Monterey on the same day has none of these issues and yet 95% of the programs, files and set-up are exactly the same on both laptop and desktop.

As I edit a lot of photos on my iMac, this is becoming very very frustrating.

Any users who have other suggested solutions would be much appreciated.

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Answer 7

Jan 9, 2022 8:31 AM in response to Hotch3f

Hotch3f, I had about 9 or 10 instances of this QuickLookUIService running, and one of them had taken a big grab of CPU %. So I force quit them all, then restarted. I have my thumbnail previews back. I was desperate because I work with a lot of images, and I have to go by eye, not file name, so not having that thumbnail was really slowing me up!

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Answer 8

Chris_C1

Community Specialist

Nov 4, 2021 6:43 AM in response to Hotch3f

Hi Hotch3f,

Thanks for updating us. Since the issue has returned, we recommend you Contact Apple for support and service.

Best Regards.

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Answer 9

Hotch3f Author

Level 1

10 points

Nov 4, 2021 2:11 AM in response to Hotch3f

Ok so that did not solve the problem as it just happened again

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Answer 10

C42D

Level 1

10 points

Nov 5, 2021 5:06 PM in response to NormanUK

I have the same issue - every single JPG in the finder no longer shows a thumbnail in icon view. Apple needs to fix this.

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Answer 11

Nov 9, 2021 10:18 AM in response to C42D

I have the same issue. Sounds like this one's on Apple

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Answer 12

Nov 11, 2021 4:13 AM in response to Hotch3f

Most of my thumbnail previews are missing too. They come back after a reboot, but suddenly disappear again. PNGs do show up, but not other image filetypes, like JPGs. Frustrating.

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Answer 13

Dec 17, 2021 11:19 AM in response to Hotch3f

This WORKED! Thank you so much!!!!

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Answer 14

capcoeur

Level 1

8 points

Dec 28, 2021 7:46 AM in response to Hotch3f

Hotch3f, thank you for sticking to it and getting a solution. Seems to be working!

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mp4, m4v missing thumbnails OS Monterey

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