Issue with RadPdfViewer Displaying Blank or Corrupted PDFs

[F3M]

We are experiencing a critical issue with the RadPdfViewer control after upgrading to version 2024.4.1113. Previously, we were using version 2017.X and everything worked correctly.

After the upgrade, when some users try to load PDFs in the viewer, the documents are either:

• Completely blank,

• Filled with black squares,

• Or displayed in a distorted/incorrect format.

The issue is inconsistent — the same PDF files that display incorrectly for some users render just fine for others. All users are accessing the same application via a Windows RDS (Remote Desktop Services) environment.

What makes this even more confusing is that:

• The issue only affects certain users on the RDS server.

• The exact same PDF can be opened successfully by one user but fails for another.

• The application and environment are otherwise identical between users.

We’ve confirmed that the issue started only after upgrading the Telerik controls to the latest version.

Can you please assist us in identifying the cause and provide any recommendations or patches that could resolve this issue?

Environment:

• Telerik UI for WinForms v2024.4.1113

• Windows Server with RDS

• .NET Framework version: 4.7.1

• Application in VB.NET (WinForms)

Please let us know if any logs, test files, or further information is required.

Best regards,
André Borges,
F3M

[Nadya | Tech Support Engineer]

Hello, André Borges,

I noticed you have two threads opened on the same topic. Your question has already been answered in the other thread you have opened on the same topic - ticket ID 1685663. Please, see my response there for more information and let's continue the discussion in the ticket. You can find it in your Telerik account.

I understand that this issue is crucial for you but I would kindly ask you to use just one thread for a specific problem to contact us. We do our best to handle all urgent cases with priority. Posting the same questions numerous times only slows down our response time because we will need to review and address two or more threads instead of one. Thank you for your understanding. 

Regards,
Nadya | Tech Support Engineer
Progress Telerik

[F3M]

Hello Nadya,

Sorry for that mistake.