G2.4.2  OS X 10.10.5
I installed a trial copy of the Letterink plugin this morning intending to try it out sometime today. Later when I opened Glyphs to resume work, G2 crashed repeatedly on opening. I finally remembered installing the plugin and removed it; now Glyphs works just fine.
I will notify the developer. You may be hearing from him.
There are two plugins written in Swift. One is LetterInk and the other is ShowOtherMasters. You can only use one of the them at the same time because of incompatibilities of different Swift versions.
I narrowed it down to ShowOtherMasters this morning and notified Martin at Letterink. He said he may try to rebuild ShowOtherMasters to make it compatible.
I don’t use “show other masters” but Letterink alone is making GlyphApp crash every time I try to open “Show Font Info” in ANY file.
Pablo, Martin at Letterink rewrote the ShowOtherMasters plugin so it wouldn’t cause the crashing with his plugin installed.
I just checked what you are reporting and I am having the same problem today – but I wasn’t having the problem after I installed his rewrite of the other plugin. I’ve worked for hours without any problems having the plugin installed. So here we go again – more troubleshooting!
At least in the recent betas, you cannot open Font Info with Letterink installed. I couldn’t test older versions yet.
@PabloImpallari: which app version are you running?
I think I fixed this. Will upload an update, soon.