PDF files attached to emails cannot be opened in some cases

[Andreas Frick]

We create almost 100 invoices a day with Nitro Pro version 12.16.9.574 and send them to our customers as email attachments.

Since shortly before Christmas 2022, I have been receiving individual messages from my customers (approx. 4 per day) that the invoices cannot be opened. My customers' PDF readers (Adobe or others) show that the PDF file cannot be opened because the file type is not supported, the PDF file is corrupt, or the PDF file was decoded incorrectly.

Where can the problem lie - it does not affect all files and the creation of the PDF files is always the same. I tell my business software to output document as PDF and this command then goes to Nitro Pro (Standard App Windows Version 10 H2 for PDF).

If I can't fix the problem quickly then I have to replace Nitro with other software because our customers get angry when this happens multiple times.

Can you help me?

PS: An update of my Nitro 12.16.9.574 to version 13 costs us CHF 90.00. I don't want to do a paid update if the problem can't be fixed with certainty.