In our testing, we found an issue in Work Folders which breaks sync after upgrade from Windows 7 to Windows 10. The root cause is the Work Folders sync partnership was not maintained, as a result, sync will stop. To fix it, user will need to go to Control panel, and setup the Work Folders partnership again. However, since the partnership has removed, there is no warning nor notification to the user about the issue.
To address this problem, we released a QFE to Windows 7, so the Work Folders client can continue to sync after the upgrade.
The QFE download is here: https://support.microsoft.com/en-us/kb/3081954
If you are using Work Folders on Windows 7, it's important to install this QFE.