I've just opened PixInsight, (PixInsight Core 01.08.03.1123 Ripley (x64) on Win7) and initially I noticed that in the Process Explorer all my Favorites appear to have been reset to defaults. The various processes that I've added to favourites myself are no longer in that list.
Furthermore, support for .xisf seems to have disappeared. If I use a file open dialog, either from the File menu, or from inside another tool such as SubframeSelector no .xisf files are shown and the file types drop down does not contain .xisf as an option.
I've seen this reported by a user on the astronomyforum.net site a week ago too. That user uninstalled/reinstalled PixInsight to resolve the problem. I'll head down that path too I think, but hold off initially in case there is any troubleshooting/diagnostics the PTeam would like me to try.
Regards,
Richard