I do have a linux box using Qt SDK having those Qt versions installed:

• 5.3
• 5.4
• 5.5
• 5.6

If I do starts to use the help system my QtC then refuse to starts commands (like builds, deploy etc).
The probleme seems to comes that my system opened files handle reach its limit.
Having a look at how many files is opened by QtCreator quickly reveal that 80% are for the Help system, which is IMOO too much for me.
I could play with my system limits to change the value, but i don't like the idea.
Also, reading some help files open a new entry in the corresponding qch entry, making the opened files growing always, but never reducing (even after closing the help file).
The same file path is also listed many times in the opened handle list, looks weird.
After some minutes (or a QtC restart), I'm again able to executecommands, until I again use help system.