When using NBS Building, NBS Engineering Services and NBS Landscape the Guidance Panel displays the following error “This is a protected NBS Guidance Page”.

This error will only apply to network installations where the NBS library files are on the server. It does not affect standalone installations.


The Guidance Panel will not show any clause guidance. Instead you see the error, "This is a Protected NBS Guidance Page".

Or you may also get a script error when you open the program.

Guidance Script error dialogue box


1) Check you have the latest version of the program and libraries installed. This fixes the issue in most cases.

Look in the bottom right hand corner of the program or log into NBS as the administrator (username: administrator, password: administrator) click on click on the Tools menu > Check for Updates.

Once you have the latest versions installed click you may need to re-cache the guidance files.

  1. In NBS click on the Tools menu > My Settings
  2. On the General tab > click Cache library now
  3. Click Copy & Replace on any further messages.

2) You may be prompted to apply a registry fix in NBS.

Guidance script warning

  1. Start the NBS software
  2. Click on Help > Show start up help page
  3. Click the Tick box to accept the Terms and Conditions for the resolution
  4. Click 'Yes' to agree to the Terms and Conditions
  5. Restart the NBS Software
  6. The guidance should now work as normal.

3) You may need to add the name of the server into the trusted sites in Internet Explorer

  1. Note the name of the server that the NBS library files are located on e.g. \\FileSVR01\
  2. Open Internet Explorer and click on Tools > Options
  3. Select the Security tab and highlight Trusted sites, then click the Sites button

    Internet Explorer Security window
  4. Un-tick the ‘Require server verification (https:) for all sites in this zone’ option
  5. In the ‘Add this website to the zone:’ box enter the name of your server hosting the NBS libraries and click Add  

    Trusted Site window
  • This will add the server to the list of trusted sites within Internet Explorer.

4) If the steps above have not resolve the issue you may also need to apply a fix from NBS.

Download chmfilefix.zip

  1.   Download the file chmfilefix.zip
  2.   Unzip the zip folder
  3.   Double click the relevant chmfilefix file depending on if your computeris 32-bit or 64-bit
  4.   Click 'Yes' to add information to the registry
  5.   Restart the NBS Software
  6.   The guidance should now work as normal.
Before using this file please read the following knowledgebase article from Microsoftexternallinkand make note of the following warnings:
  1. These changes may make the computer more vulnerable to the threat that security update KB896358 addresses.
  2. Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall your operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.
  3. Although this fix overrides the Microsoft block on CHM files running on your local network, your system is still patched with the Microsoft update for potential CHM vulnerabilities on the Internet.

Cause and more information

The NBS Guidance files are .chm files. These are blocked by default when they are read from the network.

Microsoft then released further information acknowledging the effect of this update on third party software including NBS Building, NBS Landscape and NBS Engineering Services:


The Security Update for Windows (KB896358) has caused a problem within your NBS software by blocking access of CHM files over networks. NBS guidance files are CHM files and so have been blocked from being accessed in the software on network installations.

To help you resolve this problem the NBS Software support team have created a .reg file that will update your registry based upon the instruction issues by Microsoft. A zip file containing the registry file you need is available to download below. Once unzipped, the file can be executed and will then add the information into the registry to stop the block affecting files in your local intranet zone.