Forced deactivation of parental control of windows

It would suggest one of two things, the account if a Family Account or the NTUser.dat file is corrupt.

Family Account.

If the other account is setup as a family account, sign into your Your Family at the following link:

https://account.microsoft.com/family

Under the account, click More options, click Remove from family.

Restart then check if you can sign into the account again.

Change the account privilege

It is possible there is a profile issue, you could try changing the account privileges to Standard User from Administrator to see if it logs you in.

In your current account

Press Windows key + X

Click Task Manager

Select the Users tab

Select the account, then click Disconnect

Press Windows key + R

Type: control userpasswords2

Hit Enter

Select the other account

Click Properties

Click Group Membership

Select Standard user

Click Apply then OK

Click Apply then OK again

Restart the machine, the try logging into the account.

If that doesn't work, then it suggest NTUser.dat might be corrupt.

Open Start, type view advanced system settings

Hit Enter

Under User Profiles, click Settings

For the affected profile, click Delete

Select your user profile or another user profile that is able to log on successfully.

Click Copy To..

Click Browse then save it somewhere on your drive

Rename it to something else

Open File Explorer > This PC > system drive where Windows is installed

Open the Users folder

Open the troubled profiled

Go to the View tab, then check off Hidden items in Show/Hide

The NTUser.dat with backed up earlier, copy it into this folder

Restart, then check if you can log in.