The quickest way to troubleshoot and fix this issue is by creating and testing a new account on Settings > Accounts > Family & other people. Once the new account has been created, restart your computer, and sign in with the new account. If everything is working as expected and the Start menu stops resetting, then it may be in fact a problem with your account. Your next step will be to move all data to the new account. Then delete the old account, go to Settings > Accounts > Your info, and connect it with your Microsoft account. All content on this site is provided with no warranties, express or implied. Use any information at your own risk. Always backup of your device and files before making any changes. Privacy policy info.
