Sorry to hear you keep having this issue! No one else has reported similar crashes and we haven't seen this in our testing. This leads me to believe that your Bootstrap Studio copy has been corrupted. Can you try resetting it? Here is how it is done:
Open Bootstrap Studio
Backup your custom components that you wish to keep by exporting them.
Close Bootstrap Studio.
Open C:\Users\<your username>\AppData\Roaming\
Delete the bstudio folder.
Start Bootstrap Studio again, enter your license key and import your custom components.
No crashes here so far, but I do get some quirky shut downs if I've been in the program a long time (hours, which I usually have lol). Usually I tend to close my project first now and then close the app, that way if it does crash on exiting, it won't crash my project. Haven't had any issues with crashes while using it though, only on exit and they aren't really "crashes" more like just takes so long that I finally force close it.