Failed to open any simulink files in v2015b

My problem is as below:

1. can't open any simulink files in v2015b or take long long time to open it
2. try to launch Simulink library browser in v2015b, the same issue as above.
3. event try to create a new blank Simulink file and save it, failed
4. my matlab use float license from company license serve
5. computer is windows 7 64-bit
6. try to disabled the ipv6 protocol, it doesn't work.
7. try to reinstall the matlab, it doesn't work.

Anyone could give solution for this issue, thanks!