Dear experts, I have an access 2007 application that worked well on computers with Windows NT, XP, VISTA. it's a frontend accde with a backend accde. I packaged it in a sagekey installation script so that it also installs the access runtime when someone installs it. I just tried it on a computer with windows 7 and now the application is behaving very weird: I have a form with a lot of calculated controls on it. On this computer the form seems to hang whenever I recalculate the controls. sometimes it gives #ERROR as result in some controls, sometimes it gives correct results. The form keeps calculating until I move the mouse pointer over the controls it tries to calculate. Even more strange is this: if I click the windows taskbar during the calculation, the form immediately calculates correctly and all the #ERROR controls suddenly give a correct result. It feels as if the application is trapped under water until I click on any place of the windows taskbar, and then it sort of emerges.