First of all, let me assure you that you are not alone to suffer with this issue. There are a large number of complaints about this problem.
It is believed that the issue is caused because of corrupted system files while upgrading to Windows 10, or the security updates downloaded. Restoring the corrupt files should solve the issues.
Microsoft is aware of this issue and has suggested the following methods -
Run System File Checker -SFC. It scans your system files and restores the corrupted files if any to their original versions.
Use a different account and login. If you do not have an additional account, create a new one and check if it solves the issue.
However, there are reports that both these solutions do not work for some users. I would advice you to go ahead and check if it works for your copy of Windows 10.
Some users have also suggested that it can be caused if you have AVG anti virus installed. If it is so, disable AVG and enable Windows defender.
As I said before, Microsoft is aware of the problem. With practically thousands of complaints pouring in, we can expect a fix soon.
Live....and Let Live!