I had a similar thing happen yesterday and earlier today.
First of all after updating to the latest NWjs the desktop version does not work at all for me, . Trying to load a file, I get a white rectangle on top of the interface and just sits there.
Then browser version started getting stuck at loading 99% or sometimes 80%
Tried many files/projects, same thing so it is not the projects, besides everything worked perfectly fine until this NWjs update
I solved the issue with browser version by clearing everything from chrome cache, desktop version does not work currently.
All my projects are Construct 2, but I use exporters from Construct 3 and I use absolutely no plugins/addons. Only what's already in there.