Troubleshooting PDF hit highlighting problems in dtSearch Web

Article: dts0117

Applies to: dtSearch Web


After a search, click on a PDF file in the search results list and the document appears but hits are not highlighted.

Alternatively, the PDF file may be listed in search results but when you click on it, you get an error page and the file is not displayed.

Troubleshooting Steps

1.  Check that the browser is using Adobe Reader to display PDF files on the client machine.

Currently the only way to use Adobe Acrobat or Adobe Acrobat Reader in a web browser is to use Microsoft Edge in IE Mode. 

See this article for information on setting this up:   How to use Edge to view PDF files with hit highlighting

2.  Check that the plug-in to enable hit highlighting is installed on the client machine.

Adobe Reader DC, X and XI require a plug-in to enable hit highlighting.  For information on the plug-in and a link to download it, please see

To see if the plug-in is installed, click Start > All Programs > dtSearch PDF Search Highlighter > dtSearch Pdf Search Highlighter Options.  If these options are not present in your start menu, the plug-in is not installed.

Additionally, dtSearch Web 7.67 or later needed to highlight hits in Adobe Reader.

If you have the plug-in installed and PDF highlighting still does not work, you may have Adobe Reader "Protected Mode" or "Protected View" enabled.  To change this setting, run Adobe Reader and click Edit > Preferences > Security (Enhanced).  When Protected Mode or Protected View are enabled, Adobe Reader blocks the plug-in.  There are two ways to fix the problem:
(1) Disable Protected Mode or Protected View in Adobe Reader, or
(2) Install Adobe Reader XI, and click the "Trust this host" banner that pops up the first time you open a retrieved PDF file.  This is preferable to disabling Protected Mode generally because it lets you preserve the security benefits of Protected Mode on untrusted sites.

3.  If another PDF viewer is installed, please check for compatibility information in this article:

PDF viewers that support highlighting hits

4. Check that PDF files are in a virtual directory.

PDF files must be in a virtual directory for web hit highlighting to work. A virtual directory is a folder that is visible to internet users. For example, you might have c:\docs mapped to a virtual root "/docs".

To tell if the files are in a virtual directory, look at the list displayed in search results in dtSearch Web. If the location of a file is shown as a letter drive, like "c:\docs\sample", then the files are not in a virtual root folder. If the location of a file is shown as a virtual directory, like "/docs/sample", then the files are in a virtual directory.

After creating a new virtual directory, the next step is to refresh the dtSearch Web virtual directory tables:

(1) In dtSearch Desktop, click File > dtSearch Web Setup

(2) Close the dtSearch Web Setup program (there is no need to install)

(3) Stop and restart the www service (or just reboot the web server)

Now try searching again. The PDF files in the folder should be listed in search results with the alias that you provided as their location, and when you click on one of the files it should appear with hits highlighted.