As a first measure, disable GPU acceleration in Tools -> Options ->
Advanced. PTGui will be a bit slower after that.
If you didn't already, read
https://ptgui.com/support.html#4_3
If you think this is a bug, please provide a crash log as described in
the above linked article. A detailed description of what exactly you do
until the crash happens would also be welcome.
--
Erik Krause
http://www.erik-krause.de