C# Pdf Copy & Append - Thread Safe my code

Hello I have a script (attached) that uses PdfSharp to merge one pdf to another pdf file. Right now it works 100% fine. However some times I get errors like: **Exception Details:** [login to view URL]: The process cannot access the file 'D:\sdfdfs\sdfsdf\eTickets\[login to view URL]' **because it is being used by another process.** I need you to examine the attached code: 1. Let me know if you recommend I keep PdfSharp or use a different .Net pdf lib (that's free) 2. Modify the code so it's thread safe and if a file is locked this will handle the problem properly. ## Deliverables