I just read what's been posted since here last and see at least one other person is experiencing this.
I was waylaid for nearly a month with my very ill friend, but have been working diligently on the book for the past 2 weeks trying to make up for lost time, so still can't take time out for troubleshooting but WILL do that when I finish the book.
I am just reaching the end of the phase of inserting pictures and have noticed two things:
1. There doesn't seem to be any rhyme or reason at all as to when Sigil crashes. I am going through the same motions regardless, and sometimes it crashes and sometimes it doesn't. (I realize there IS a reason, just saying it's not related to keystrokes or a particular action I am taking, [aside from it happening only when the window opens that allows you to select a picture].)
2. I noticed the longer I am working in Sigil, the more frequently it crashes. I might work for 2-3 hrs without a hiccup, then I get a crash... then another, then another... and they start happening closer together until it's crashing with nearly every other picture I place. And again... nothing is different about the types of pictures or my routine in placing them.
3. The Adobe Photoshop angle has also been eliminated, as yesterday when it kept crashing I started closing Adobe between needing it, so that when I went back to Sigil to add exisitng files and insert pics, Adobe was closed. And it crashed anyway.
FTR I am using Windows Ultimate 64, and Firefox v50.1.0. No real-time AV as I use Sandboxie, but have scanned the computer on-demand with no viruses. No other programs are giving me problems. Graphics driver is up to date for the hardware (this is an older laptop with shared RAM/nVidia integrated - no discreet graphics card).
Will certainly come back and use the links provided to enable Windows debugging and also check the standard Win system logs when time allows. It's kind of nice to know I'm not the only one this is happening to.
