By john 
You turn on the preview pane in File Explorer so you can glance at documents and photos before opening them. But when you select a file, the pane on the right stays blank, or it shows “No preview available.” When Windows 10 File Explorer preview pane not working forces you to open every file, browsing through folders becomes much slower.
The preview pane relies on small add-ons called preview handlers. Windows includes handlers for images, text, and some media, while programs such as Microsoft Office and PDF readers install their own for their file types.
If a handler is missing, broken, or disabled, that file type shows nothing. A slot setting in Folder Options can also stop previews entirely, and so can a security setting that blocks previews of files downloaded from the internet.
Turning the right options on and repairing the program that owns the file type fixes most cases.
What Might Be Causing It
The preview pane stays empty for these reasons:
- “Show preview handlers in preview pane” is turned off.
- The program that provides the preview, such as Office or a PDF reader, is not installed or is damaged.
- “Always show icons, never thumbnails” is ticked.
- Files downloaded from the internet are blocked from previewing.
If only PDFs fail, the problem is almost always the PDF reader’s preview handler rather than Windows itself.
First Steps to Try
Check File Explorer’s options.
- Open File Explorer, select the View tab, and turn on Preview pane.
- Select Options > Change folder and search options and open the View tab.
- Tick “Show preview handlers in preview pane.”
- Clear “Always show icons, never thumbnails.”
- Select Apply, close File Explorer, and open it again.
Test with a simple text file or photo to confirm the pane works for built-in types.
If the Problem Continues
Repair the preview handlers for each file type.
- For Office files, open Settings > Apps, select Microsoft Office, choose Modify, and run a Quick Repair.
- In your PDF reader’s preferences, turn on the option to show PDF previews in Windows Explorer.
- For downloaded files, right-click the file, choose Properties, and tick Unblock if it is offered.
- Restart Windows Explorer from Task Manager.
- Run sfc /scannow if built-in types such as images also fail.
Remove third-party preview add-ons you no longer use, since a broken one can affect others.
Protect Your Data First
Only unblock files you trust, because previews of malicious documents can still be risky. Preview settings do not change or delete the files themselves.
The Bottom Line
An empty preview pane usually means preview handlers are disabled or missing. Turn them on in Folder Options, repair Office or the PDF reader, and unblock trusted downloads.