When logged on as system administrator trying to change parental controls on a user account or set them up on a new user a/c I have recently started receiving the message "unable to alter parental controls. if the problem persists see administrator" accompanied by the dreaded yellow tringle enclosing exclamation mark. Setting up a new administrator a/c doesnot help. Any ideas on how to fix what appears to be a bug also being experienced by many others?

to be accurate the notice is

"Unable to make changes to parental controls settings. If this
problem persists, contact your system administrator."

Maybe the other acc that you are trying to put p.c. is an administrator?

I believe you cant put p.c. on admins.

To troubleshoot the issue, try disabling User Account Control TEMPORARILY. You can do this by accessing the User Accounts applet in Control Panel. If it works with UAC disabled, then I'd suspect that there was a corruption within Windows. You may be able to fix it by running "sfc.exe /scannow" (without the quotes) from the Start search dialog. Just press Enter after typing it in (with UAC disabled).