PDF files do not appear in dtSearch Desktop/Network after installation of the Microsoft Windows 2026.01 Security Update

Article: dts0246

Applies to: dtSearch Desktop/Network

PDF files do not appear in dtSearch Desktop/Network after installation of the Microsoft Windows 2026.01 Security Update 

Last Update:  January 15, 2026

After installation of the Microsoft Windows 2026.01 Security Update (KB5074109), PDF files appear as a grey box in dtSearch Desktop/Network.  This affects all versions of dtSearch through the current version, 2025.02.

Reinstalling or updating Adobe Acrobat and changing security Acrobat settings has no effect on the problem.

The Windows 2026.01 Security Update addresses many security vulnerabilities in Windows so we do not recommend uninstalling it.

Options

1.  View PDF files as plain text or in a separate Adobe Reader window

dtSearch has two alternative PDF viewing options that still work: (1) viewing PDF files as plain text, and (2) viewing PDF files in a separate Adobe Reader window.  To select one of these options, run dtSearch Desktop and click Options > Preferences > PDF view options.

If you select the option to view PDF files as plain text, you can still click the Launch button or press F8 to open PDF files in Adobe Acrobat or Adobe Acrobat Reader.

2.  View PDF files as formatted HTML (preview/beta feature in dtSearch 2025.02)

dtSearch 2025.02 includes another PDF viewing option as a "preview" feature that may be preferable for some users.  It displays PDF files as formatted HTML, more closely following the formatting of the original file. However, it cannot display most PDF images and the formatting is approximate.  To enable this feature (1) run dtSearch, (2) close the Search dialog box, (3) press F7, (4) enter "FPDF_1" in the text box and click OK.  After making this change, you will have a new option in Options > Preferences > PDF view options, "View PDF files as formatted text (preview/beta feature)".

The formatted HTML display option does not affect indexing so you can turn it on or off as needed without the need to reindex.

3.  dtSearch 2026.01 beta (not yet available)

dtSearch 2026.01, which has not yet been released, uses an internal PDF viewer and is not affected by this issue.  We will update this article with additional information when prerelease versions of dtSearch 2026.01 are available for testing.

For notifications of new version releases, you can sign up here: https://www.dtsearch.com/dt_subscribe.html