PDF Preview deactivated with Windows update

[jennifer_2464]

My computer restarted after windows updates and now I'm unable to preview pdf's as before. I have tried resetting View Options... in different options as suggested by multiple forums. None have been able to re-activate the Preview Pane option. In Adobe preferences, I've checked and unchecked "Enable PDF thumbnail previews in Windows Explorer" without success.

Coworkers are now experiencing the same thing after the automatic updates occurred after-hours. Suggestions or alternatives to opening each file?

[Randy Hagan · Accepted solution]

The first thing I'd try would be to first open Acrobat, then open a Windows File Explorer window.

You want to use the other toggle switches you describe in your post. Toggle your View Options to show large or extra large icons. Check the Enable PDF thumbnail previews in Windows Explorer check box and open your Preview Pane. The important things we want to test is whether the images show up in your dialog box in the Files Pane and/or the Preview Pane.

Sometimes doing this once will get you your previews. More often, you may find you have to open Acrobat every time you want to see a PDF preview in the Preview Pane. You'll know your course of action after you try this process a time or three.

Hope this helps,

Randy

[jennifer_2464]

Although it has not solved the issue with previewing files in the preview pain, your suggestion did trigger preview of word & excel files. On a positive note, switching View Options does allow me to catch a glimpse of what the file is.

I will explore all possibilities and let you know if I get it back to the previous settings.

Thank you!

[Randy Hagan]

Cool. I'm rooting for you.

Hope it works out well for you,

Randy

[jctech2025]

Hi All,

I have several staff members that are having this issue.  I tried everything including reinstalling.  Even after reinstalling, they are all getting this message 

The file you are attempting to preview could harm your computer.  If you trust the file and the source you received it from, open it to view its contents. They are even getting this message when its a file they created.  Thoughts?

[donald_7424]

I had the same problem, thank you for solving!!!

[nicole_7070]

I'm having this same issue and its very frustrating because I use the preview pane all day long for my pdf's.  I have checked all settings in file explorer and adobe and they are correct.  I now have to open each pdf file to view it, which defeats the purpose of the preview pane and is time consuming and I never had to do it before. 

[jennifer_2464]

I understand the frustration Nicole, especially the extra time consumption. I'm switching all my setting arounds to trigger the resetting and I hope to find the correct ones to share.

Please let us know if you come across the correction for this, thanks.

[debra_1043]

I am having this exact issue and have tried ALL the fixes posted here and nothing is working.  Very frustrating!  

Any other fixes available?  I pay for the Adobe Pro version for my work and having to open EVERY .pdf is very frustrating! 

Thanks for any help

[Zebas25760351gfs2]

I am having the same issues and have tried multiple fixes with no luck!! It is so frustrating and time consuming to have to open every .pdf!!! Hopefully someone can figure out what is making this happen. Thanks for any help.

[jepwea]

I tried everything else suggested - this is the only one that worked for me: 

Here is a simple solution that worked for me -

in the file explorer, 3 dots >> Options>> View Tab. Just disable (aka UNcheck)  this check box for Folder Settings "Show Preview Handlers in Preview Pane".

(This happened on windows 10 as well!)

I also did this....but now I'm behind on security updates until next time.... I un-installed the 25H2 updates and everything works GREAT!!

The issue was caused by Windows Security Update (KB5066835). To solve this issue for (User), I went into Settings > Apps > Advanced App Settings > Uninstall updates. Within the Uninstall updates area I found the Security Update (KB5066835) and uninstalled it. It prompted to restart the device. After the uninstall it worked! 

“Starting with Windows security updates released on and after October 14, 2025, File Explorer automatically disables the preview feature for files downloaded from the internet,” Microsoft told Windows Latest in a statement. “If you are confident in the safety of both the file and its source, you may remove the internet security block.”

How to unblock previews in File Explorer

If you trust the file, you just need to right-click the file in Explorer, select Properties, and check ‘Unblock’ under the security section.

While it’s a simple workaround, it still defeats the whole purpose of ‘quickly‘ previewing files in Explorer. If you need to click four times to see a preview, you might as well open the file, which would not take more than two clicks. However, thankfully, there’s a PowerShell script that lets you unblock all files in a specific path.

In PowerShell, you just need to run the following command:

 Unblock-File -Path "C:\Users\admin\downloads\*.pdf"

It will unblock all .pdf files in the downloads folder, including those you plan to download in the future. As long as you trust what you download, this should be good to go. You can run the same script for other paths or file types.

[CPAservice]

this worked for me. Files are on a server computer. Opened PowerShell (admin)

C:> Get-ChildItem "$env:C:\Folder-A" -Filter *.pdf -Recurse | Unblock-File

The name 'Folder -A' is a generic label for one of many folders in my server's C-drive.

I restarted the server and the workstations. So far, its still working

[AL214]

Hi! I entered the command with my folder path into PowerShell, however, nothing happened. Any suggestions?

Thanks for your time and input; much appreciated!

[TW9_LLC]

I have the same problem - I also pay for pro version 

[gaston_8056]

Il est marqué problème résolu mais j'ai le même problème et ça ne fonctionne toujours pas.

C'est suite à la mise à jour windows...

[chantal_1382]

Bonjour

Concernant le problème d'aperçus pour les fichiers pdf dans l'explorateur Windows, en attendant qu'une solution définitive soit trouvée par Microsoft, j'ai trouvé une parade, certes pénible mais qui fonctionne. (Yes !!)

Je vais dans l'explorateur et double clic sur le fichier dont je n'ai pas l'apercu. Il s'ouvre dans Adobe acrobate et je le ré-enregistre sous le même nom dans le même dossier que celui d'origine (on va nous dire qu'il existe déja, répondre oui pour supprimer l'ancien fichier). Ah ce moment là dans l'explorateur windows, j'ais alors de nouveau l'aperçu.

Mais j'espère que Microsoft trouvera vite une parade pour ce problème qui à priori ne se voit que sur les pdf téléchgargés de mails.

[monika_3023]

I am having the same issue, I work with pdf files most of the time, need to rename it according to their content, so it is very frustrating not being able to do it as I am used to, but need to open it to see, make notes on paper, then close and rename.... are we not living in the 21st century any more surranded by robots any more?
My observation is that pdf files that were created by "print to pdf" action is still previewable, but not one that were downloaded from different platforms, even though I created them.
I have been trying to find solution in the last two days, never thought of that it was caused by a Windows update, but maybe we should start questioning Microsoft then?
I hope you find a solution and let us all in trouble know.

[jennifer_2464]

Thanks for providing feedback everyone! There is an update in adobe this morning and after updating it my coworker was able to preview downloads from after the udpate, but not files from yesterday or before. I did the adobe update on my pc and it did not change anything.

I'm hoepful and will continue to search for the solution. Best of luck!

[monika_3023]

I uninstalled and reinstalled Adobe Acrobat Reader today - no changes. Installed PowerToys - no changes. Tried all suggestions one can find on Google - nothing helped. I feel totally lost. 

[Randy Hagan]

If new files work and previous ones don't, you may want to open problematic files in the new version of the program, use the File>Save As... menu command to save a new version over the top of the old one, then try again.

Hard tellin' not knowin' for sure, but saving the file in the version that allows snapshots in the Preview Pane may get you the right result with the old files too.

Good luck,

Randy

[tanya_5299]

I'm in the same position as you. I have more than 2600 pdfs te rename. It would take me a month to do it by writing it down first. This is ludacris!!! I spent the entire day watching online tutorials and reading on forums to try the find the solution. No avail. Losing my mind! I literally can not work now. This is a issue to users all around the globe. How can Microsoft do this and leave us with absolutely NO working solution?????

I have tried everything that I have come across, nothing works. 

[m.t_th�o]

La seule solution est la suivante : Ignorez la dernière version de
Windows (vers 18-10-2025)

- 1 : Supprimez la mise à jour.
- 2 : Désactivez les mises à jour automatiques de Windows car quelques
heures après, la même mise à jour se télécharge automatiquement sans poser
la question, prête à être installée.

Le problème sera résolu

[Zebas25760351gfs2]

This is the information I found from a Microsoft chat. Go to the Internet opinions in your settings - go to the security tab -  click in trusted sites - I clicked on sites - unchecked the box at the bottom that states require server verification (https:) for all sites in this zone - then added the IP address from my network. This let my preview pane accessable and I also able to preview word and excel documents.  Hope this helps! 

[m.t_th�o]

Merci pour l'information. Pouvez-vous préciser svp quels "paramètres" ?

[jace_4656]

I wanted to share a temporary workaround for the Adobe issue we've all been experiencing. While it's not a permanent solution, it worked for me at least until a patch is available from Adobe.

1. Go to your computer's settings.

2. Navigate to Windows Updates --> Update History

3. Scroll down and click 'Uninstall Updates' and click uninstall the most recent "Security Update for Microsoft Windows"

3. Reboot your computer.

You'll still have the previous security updates, but this will remove the specific update that seems to be causing the current problem. I hope this helps until Adobe provides an official fix.