using doc2any with the "-checkpwd" option we can avoid hanging on the GUI if there is a password on the file; however, the program gives no output indicating that this is why the program failed to convert the document. Is there any way to know that this is why the conversion failed? Is there any way that you could add some text on stderr to tell us that this is why it failed? We're trying to report back to the end-user that the file contained a password... but right now there's no way to distinguish that type of "failure" from any other failure to convert the document.
Please add "-debug" parameter to your command line options, "-debug" parameter will print more detaled information to console, for example,
Doc2any.exe -debug -checkpwd C:\test.doc C:\out.pdf