Using Windows 8.1, your task manager might show that a whole lot of CPU capacity is taken by a process called taskhost.exe
According to Microsoft’s official article, this happens if a local account username of Windows 8.1 contains the word “user” (believe it or not).
This is quite weird, but the official solution method is even more weird: “Do not use user names which contain the word ‘user'”… In my opinion, this is a farce.
Unfortunately, I cannot offer a better solution, but can at least give some hints what you should not forget if you change to another username:
- Check your scheduled tasks. They are often run with certain user privileges and given passwords, so make sure you change it to your new user account
- Check your Windows services. Most of them run under SYSTEM account, but can also run as other users.
- Check your directory and network share permissions, if this user has any special ones.
- Make sure you do not lock yourself out of Windows. In many cases it is useful if your immediately add your new user to the Local Administrators permission group.
A reboot is necessary afterwards to tame taskhost.exe (only logging off does not help).