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Most libraries from Telerik Document Processing are affected after you install January 9, 2018, .NET Security and Quality Rollup (KB4055002). Applications that request a fallback font or a character that is not included in the currently selected font return the following error messages:
“FileFormatException: No FontFamily element found in FontFamilyCollection that matches current OS or greater: Win7SP1”.
Inner exception originates from: CompositeFontParser

Solution 1:

Microsoft has released an update which fixes the issue. More information about it you can find here: Description of the Security and Quality Rollup for .NET Framework 4.6, 4.6.1, 4.6.2, 4.7, and 4.7.1 for Windows 7 SP1 and Server 2008 R2 SP1 (KB 4074880).

Solution 2:

To keep .NET 4.7.1 installed and maintain protection against vulnerabilities that are addressed by the January security updates, uninstall the January .NET Framework Security and Quality Rollup (KB 4055002), and then install the January .NET Framework Security-Only Update (KB 4054183). To do this, follow these steps:

  1. In Control Panel, open the Windows Update item, and then select View update history.
  2. In the Review your update history list, locate and select Security Update for Microsoft .NET Framework 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1 (KB4055002). Then, select Uninstall.
  3. When you are prompted for confirmation to uninstall, select Yes.
  4. Restart your computer if you are prompted to do this.
  5. Download and install the Security Only update for .NET Framework 4.6, 4.6.1, 4.6.2, 4.7, and 4.7.1 for Windows 7 SP1 and Windows Server 2008 R2 SP1 and .NET Framework 4.6 for Windows Server 2008 SP2 (KB 4054183) for your operating system configuration from the following links:
    Security Only update for .NET Framework 4.6, 4.6.1, 4.6.2, 4.7, and 4.7.1 for Windows 7 SP1 and Windows Server 2008 R2 SP1 for x86 systems (KB4054183)
    Security Only update for .NET Framework 4.6, 4.6.1, 4.6.2, 4.7, and 4.7.1 on Windows 7 SP1 and Windows Server 2008 R2 SP1 for x64 systems (KB4055269)
  6. Follow the installation prompts, and then restart your computer if you are prompted to do this.

Solution 3:

 Roll back to the previous version of .NET Framework. To do this, follow these steps:

  1. In Control Panel, open the Programs and Features item.
  2. In the Uninstall or change a program list, locate and then select Microsoft .NET Framework 4.7.1, and then select Uninstall/Change.
  3. Select Remove .NET Framework 4.7.1 from this computer, and then select Next. 
  4. Select Continue to confirm the uninstallation.
  5. Select Finish after the uninstallation is finished. 
  6. Restart your computer if you are prompted to do this.
Top achievements
Rank 1
 asked on 16 Jan 2018
6 answers

The documentation for the libraries included in Telerik Document Processing is available at

This week's latest resources are described below.

The content of this article is updated to describe the new properties added to the TextFragment class.

Headers and Footers
The article is introduced to describe the new feature in RadSpreadProcessing - applying headers and footers when printing a document or exporting to PDF.

A new help section that explains how you could use the new RadSpreadStreamProcessing library to achieve fast export of spreadsheet documents with minimal memory usage.


Telerik team
 answered on 15 Sep 2017
4 answers

I've a .NET core web-api project and I need to edit the existing pdf (like adding an image/ text) without using UI. The pdf files are stored in Azure Cloud which I can access through URI.

So, is that doable? Would appreciate if you could point me to the right Telerik libraries and any examples would be great.


Telerik team
 answered on 11 May 2021
1 answer

I'm using Telerik UI for Blazor and have to create some PDFs (via RadFixedDocument and PdfFormatProvider). This works fine so far.

But I also have to display a preview of the Document on my blazor-generated website (server side, not WebAssembly). It doesn't matter if this is a preview of the FixedDocument or of the generated PDF.

Does a control for "Telerik UI for Blazor" exist which can display the RadFixedDocument or the PDF? Or is there a possibility to export the RadFixedDocument or the PDF to an image and I can display this image? Or is there another way for making the created Document visible for preview?



Marin Bratanov
Telerik team
 answered on 11 May 2021
2 answers



I would like to insert a jpg at specified or predefined (field) location in the PDF, is it possible?

My code based is .Net Core c#, thank you.

Telerik team
 answered on 11 May 2021
1 answer



Is there a way to overwrite existing files when unpacking from a zip with ZipFile.ExtractToDirectory()?




Telerik team
 answered on 07 May 2021
1 answer


Is it posible to check if pdf file is password protected using Telerik Tools?


All the best

Telerik team
 answered on 22 Apr 2021
1 answer

Hello! We are having an issue while using DocxFormatProvider to convert docx to RadFlowDocument. When the provider converts, it replaces all charts in the document with blank paragraphs, and we can't catch this case. (doc for example sample doc)

public void Sample(byte[] document) {
    var docxProvider = new DocxFormatProvider();
    var radFlowDocument = docxProvider.Import(document);
Telerik team
 answered on 21 Apr 2021
5 answers

Not sure that this actually qualifies as a bug, but it was unexpected behavior.  For unit testing I was creating an empty Workbook document and writing it to a file.  It turns out, that the file is corrupt unless it has a Worksheet added to it.  The XlsxFormatProvider does not issue any error and happily writes a 3k file, but Excel can't read it.  Excel throws a dialog "We found a problem with some content in the 'test.xlsx'.  Do you want us...".  Selecting Yes eventually comes back with a "The workbook cannot be opened or repaired by Microsoft Excel because it is corrupt." message.

Simply adding a worksheet:


will allow it to create a file that Excel will handle.  Again, not sure you could call this a bug, but it wasn't what I expected it to do.  It might be better if the XlsxFormatProvider threw an exception for trying to write out an empty file.  

At any rate, figured I throw this out there in case anyone else runs into this behavior.

Top achievements
Rank 2
 answered on 13 Apr 2021
1 answer

I am making a catalog of pictures.   During the process the user can either select on file or multiple files sorted by category.  


Why would the pdf files be so much larger than the Word files?  It’s usually the other way around!  


I combined the individual pdf files and it became 45MB.  I combined the word files and it was 37MB.  I then turned the 37MB word doc into a pdf and it became 4MB.  So as output from Smartview(my program) the pdf file is 45MB but generating a pdf from the word files it is 10x smaller!!!!  

Telerik team
 answered on 13 Apr 2021