This thread is a year old, and people keep replying to it with what are likely to be unrelated cases.
It's best to start a new thread, or file an issue following all the guidelines if you can.
Also as ever, it's very difficult to help or even make any kind of comment unless you provide either:
1) the affected project, or
2) press F12 and include any error messages that were logged
Since replies to this old thread aren't particularly helpful, closing this thread.