note fish For those of you who are interessted in the topic. I solved the problem by myself.<br/><br /> <code>sysopen(FH, $file, O_WRONLY|O_EXCL) or die $!;</code> works fine for me and it even works if the file is opened via a shared folder.<br /><br /> Finally I want to apologize for my offtopic-postings. I thougt the "fileInUse"-check would be possible with a Win32::OLE-function and because of that I posted here and did not create a new thread. I hope I will do better in future.<br /><br /> Best regards from sunny Germany. 153486 784588