Well, this is what I have found so far. The Registry key permission setting does indeed stop my program from writing to its Registry key. On my two WinXP and my Win7 systems the Registry key permissions are set to "full control". Registry editor does not allow me to manually change the "full control" permission to "Read". The "full control" permission is checked but disabled (dimmed) so I can't change it and I don't know why. I had to find a utility that changed the permission outside of registry editor. When the key permission was changed to "read" then writing to the Registry failed. CWinApp:WriteProfileInt() fails with a "read" permision but there is no error code associated with the failure (i.e. GetLastError() doesn't return an error code). I think the only thing I can do is detect the Registry write failure, report it to the user, and use an INI file instead of the Registry. I don't particularily like it but I think that's my only choice.

I KNOW I sould be looking at the customer's setting. The problem is that I'm not getting any support from him. So, I need to understand the settings on my computer so I can run some tests and make suggestions to him. My problem is that I'm not very well versed in "security" settings in Windows 7. I still think it is a user permission setting in Registrey - but I'm not sure where to look yet.

I don't think UAC is the answer. I looked at my UAC settings and didn't see anything other than how to set the warning levels. Mine is set to: "Default: Notify me only when programs try to make changes to my compputer". Even with this setting my program never causes the UAC to display the notification. I think the problem lies in the Registry p0ermission settings, but I don't know yet.

This may be in the wrong forum – but here goes. I have a 32-bit application that I've been maintaining for about 12 years and it runs on every Windows platform up to Windows 7. In all that time I've been using CWinApp::GetProfileXxxx() and CWinApp::WriteProfileXxxx() calls to read and write my program settings (about 70 settings) in the Registry. The settings are read from the Registry at start-up and written to the Registry when the program closes. There is also a method for the user to read and write the program settings to an INI file using the same code as the Registry access. On my Windows 7 system the Registry read/write works just like it always has on all previous Windows versions. However, on some customer's Windows 7 machines there appears to be a problem with the Registry access. The program settings are either not being read from the Registry or are not being written to the Registry. I think the settings are not being written – but I don't know that. When the user uses the INI file the settings appear to be read and written. The customer has complained a bit (I'd complain too) but doesn't have the time or doesn't want to take the time to run some simple tests for me to find out what's going on with his Windows 7 system. So here is my question: Are there any user account settings or permissions that can block the program's access to the Registry? He claims he is an Administrator but I can't even get him to verify that. Thanks, Mike