PDFTron virtual printer en x64

I'm using PDFTrong printer to convert office document with PDFSDK.
When the user try to convert office document I check the return value from PDFSDK to to notify that office is missing, but on x64 machine the PDFSDK takes about 2 min to detect that office is missing.
Any idea why the behavior isn't the same on x64 ?

Thanks in advance

PDFNet does not offer methods to check if MS Office is installed on a given system.

PDFNet convert methods will try all possible methods (including printing via virtual driver) before passing the program control back to the caller.

If you want to check if Office is available/installed you could use MS Office .NET or COM/OLE API.