Idea64 11.0.2 hangs after autocomplition Follow

In our company some developers use IntelliJIdea and have a troubles with hanging idea64 over Windows 7x64 Professional.
I have lost a lot of code after idea hangs.
The last time It happens after I print St (+Tab) .
The "String" was appears in the code but in this moment idea hangs.
Some time Idea work without hangs for some days. And sometime it hangs for some time per 15 minutes.

What can it be?