Paul, Not seen this on the wiki but that is an awesome tip. Save a lot of thrashing around with acrobat. Henry -----Original Message----- From: therion-bounces@speleo.sk [mailto:therion-bounces@speleo.sk] On Behalf Of Footleg Sent: 23 September 2014 17:09 To: List for Therion users Subject: Re: [Therion] metapost error on Windows7 .... For those who run Therion on Windows and have not already seen the PDF viewer tip on the wiki, I use Sumatra PDF reader which is the only reader I have found on Windows which does not lock the PDF file when it is open in the reader, and that renders the PDF correctly as well. Using Sumatra I can keep the PDF window open and each time I recompile my project the PDF display refreshes automatically which is really handy. Footleg ....