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Keep bookmarks names after concatenate

Hi all,
In my project I merge two pdf files with concatenate. Both files contain bookmarks with the same names. It works fine but after merging, bookmarks names in the second pdf will be changend.

For example:
bookmarkName will be changed in bookmarkName1, bookmarkSureName will be changed in boomarkSureName1 etc.
Is there a way to keep all bookmarks as they named in the original files?

Thanks in advance


Thanks for contacting support.

Would you please share your sample PDF documents with us. We will test the scenario in our environment and address it accordingly.

Any news regarding boomark?



Thanks for getting back to us.

As shared earlier, would you kindly share your sample PDF document with us. This would help us observing the issue in our environment (if any) and address it accordingly.

Please find attached my sample documents and the code I use to merge documents.
The second document would be "document2.pdf

Dim pdfEditor As New PdfFileEditor
Dim Document1 As String = “C:\Document1.pdf”
Dim Document2 As String = “C:\Document2.pdf”
Dim PDFOutput As String = “H:\MergePDF.pdf”

pdfEditor.Concatenate(Document1, Document2, PDFOutput)

Document1.pdf (57.2 KB)
Document1.pdf (57.2 KB)



Thanks for sharing requested information.

We have checked the files shared by you and noticed that shared PDF documents did not contain any bookmark (please see the screenshot). NoBookmarks.png (18.3 KB) Would you please share valid PDF documents which contain bookmarks.

I’m sorry it was my mistake.
I didn’t mean bookmarks, I meant the names of form fields.
After merging two pdf, form fields with the same names in the second pdf will be renamed

Document1.pdf (52.9 KB)
Document2.pdf (53.0 KB)

I hope its clearer


Thanks for sharing details.

We have tested the scenario in our environment and were able to replicate the issue. We have logged this issue as PDFNET-45683 in our issue tracking system for further investigation. We will let you know as soon as we have some significant updates regarding its correction. Please be patient and spare us little time.

We are sorry for the inconvenience.