My Photostructure library is on an external hard drive, which gets automatically plugged into my laptop when I dock it.
Currently photostructure keeps on crashing if I undock my laptop, and I don’t remember to turn it on next time. I’d like it to not crash, so that it is always available whenever I’m docked, without me having to re-launch it.
Thanks for posting so many good ideas, Mitko!
I prefer the term “proactive shutdown”. 
But I’ve thought about this, and I think you’ve changed my mind.
I had been following the unix mantra of “fail fast” in that if the library directory isn’t present, there’s nothing PhotoStructure can do, so it should just shut down.
However: it might be more user friendly to stay running so it can present the user with an error diagnostic page, very much like what the Desktop edition does at launch when the library directory is missing.
Thanks for the suggestion, this is on my todo list now!
This would seemingly also cover PS libraries that are stored on disks/volumes/shares that are encrypted and/or otherwise require manual intervention in order to be mounted.
Btw, I filed a bunch of suggestions but this is my main blocker for adopting PhotoStructure on a regular basis, since every time I unplug it dies.
After this bit me the Nth time, I implemented in v2.1.0-alpha.8. Related: ✅ Disable PhotoStructure from "failing fast"