multiple windows accounts vs avast

I’ve got 2 accounts on my windows - I share this with my wife so both accounts are used most of the time - I don’t log off at all.

When I log in into one account the avast works normally.

When I log in and switch to second account avast loads and consumes 100% of the CPU - the tray icon shows but its not possible to run safe zone or avast menu.
This happens only for the second account.

To be able to use avast in the second account I have to log off from the first one.
This is a serious limitation.

I use Avast Pro with all latest updates
Windows 8.1 64 Bit

Reinstalled everything and still the same problem.
Anyone?