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Viewer v3.5.0 only renders 2 page from pdf files



I am using groupdocs sample solution with viewer v3.5.0 for ASP.Net.
even in sample solution it only able to render first 2 pages from the files.

there is no code change in sample solution done from my side and licence key is also added.

despite from this when i added viewer v3.4.0 DLL, without changing any code it does work for me.
it looks like there is something related with v3.5.0 DLL.

could you please take a look and let us know if there is some specific change set i am missing to implement with v3.5.0

attached is a sample file. its size is 529page but only first 2 page render in sample solution with v3.5.0

Puneet Rajak


Hi Puneet,

Thanks for raising your issue.

I have tested your scenario with GroupDocs.Viewer for .NET 3.4.0 and 3.5.0 and found that issue is not related to back end API or its any specific version. The issue occurs when showThumbnails is set to true. In this case, when application starts generating thumbnails, it pauses rendering of pages and after generating all the thumbnails it resumes the rendering process.

The documents with small number of pages takes negligible amount of time for generating thumbnails. However, the amount of time increases with the number of pages and, in your case, 529 pages takes a considerable amount of time. Hence, rendering process is paused for a long time.

Therefore, I have logged it as a performance issue on GitHub. we shall look into it and once we have any updates on it, we’ll notify you here. You can also follow this link for further updates related to this issue.

In case of any confusion, please let us know.

Warm Regards


Hi Usman,

Its been a month getting update on our raised issue.

Please let us know about the release date of fixes of this issue
and also do let us know when would be v3.6 would be available with improved performance.

Puneet Rajak


Hi Puneet,

We apologize for the delay.

I am afraid that currently we don’t have any updates regarding the release date. As far as performance is concerned, we are working over it and providing improvements in each version of the API. For improvements introduced in v3.6.0, please see release notes.

In case of any further question, please let us know.

Warm Regards


Hi Usman,

I have tried Groupdocs sample solution for v3.6.
Though it still does not display me more than 2 pages while my PDF file has 26 page in it.

please download the solution from your shared location

and try to render attached pdf file for more than 2 pages.
if your sample solution is able to render the complete document correctly(i.e. 26 pages)
than please let me know what changes do we require from your sample solution to fix this.

if it is replicable on your machine as well than please let me know.

Also please let us know if you got any update from development team against above post.

Puneet Rajak


Hi Puneet,

Thanks for sharing your issue with us.

In your provided screen shot, we can see that evaluation message is appearing at the top which means you are using the API in trial mode. In trial mode your are able to render only 2 pages of the document. Therefore, please verify following things in your application.

  • Path to license file is correct.
  • License is not expired.

If their is no issue with the license then go to storage folder and remove temp folder and render the document again. Hope this will resolve your issue.

Furthremore, currently, we don’t have any updates for the issue you mentioned in previous post. Once we have any information, we will update you here.

In case of any confusion, please feel free to contact.

Warm Regards


Hi Team,

Can you give the customer an update on this issue .



Hi John,

The GroupDocs staff member has updated the customer on the issue being reported in this forum thread which is logged in GitHub Issues as Please see this comment.

If you would have any other questions, please let us know.

Warm Regards