[DiapDealer]

Interesting! Thanks for hammering away at it. The QT_LIB directory in the the /usr/local/bin/ sigil launch script is determined by CMake when building Sigil. CMake has to be able to find the correct qt libs to be able to build Sigil against them. So why that same programmatically determined directory wouldn't work when running Sigil has me puzzled to say the least. I'll have to do some looking around.

As far as the multiple Qts go, that's fairly common on Linux, actually. Some sort of "alternative" program takes care of changing to different Qts (as well as defining a default Qt version). You may want to check which one is currently set as active on your system, though.