I am going to assume that you are using Chrome
What has happened is that your profile has become corrupt or lost.
Note: Before trying this solution for chrome your preferences cannot be read, take a complete backup of your all Chrome data including the bookmark, history and all.
What you need to do is re-create Chrome profile folder.
In order to do this you need to be able to view hidden files: -
- Go to Control Panel > Folder Options & click the “View” tab.
- Tap on Show hidden files, folders, and drives and then Uncheck the Hide protected operating system files. Then click on ok.
Now to fix the profile: -
- Close Google Chrome.
- Navigate to C:\Users\<Your_Username>\AppData\Local\Google\Chrome\User Data
- Rename the “User Data” folder to “User Data.OLD”.
- Restart your chrome.
- Restore your backup of bookmarks etc
I really suggest you install two recommended extensions to chrome: -
LastPass
Xmarks