Hi,
Thank you for your interest in Windows 10 Technical preview.
I suggest you to place the computer in Clean boot and check if issue persists.
Putting your system in Clean Boot state helps in identifying if any third party applications or startup items are causing the issue. You need to follow the steps from the article mentioned below to perform a Clean Boot.
How to perform a clean boot in Windows
http://support.microsoft.com/kb/929135/en-us
Note: After clean boot troubleshooting steps, refer to the section "How to reset the computer to start as usual after troubleshooting with clean boot" in the provided link to return your computer
to Normal startup mode.
If issue still persists, I suggest you to run SFC scan.
System File Checker is a utility in Windows that allows users to scan for corruptions in Windows system files and restore corrupted files
Run the System File Checker (SFC) scan to fix any corrupted files. Follow these steps:
https://support.microsoft.com/kb/929833?wa=wsignin1.0
Hope this information is helpful. Please do let us know if you need further assistance, we’ll be glad to assist you.