Hi I know now where the problem was. DTM_SETFORMAT should be &H1005. I looked it up at commctrl.h. My mistake. I just copied the previous value somewhere in the internet. :laugh:

Zoltan Balazs wrote: I think you are wrong here, the LocalSystem account is the highest privileged level that a service can get. You'd think that's the case, but there have been too many questions about "Access Denied" errors when using it to get at various parts of the file system, registry, and of course, network access. In practice, unless you REALLY need Desktop Interaction, it's best to create an account explicitly for the service to use so you have greater control over what it can and cannot get to. Truthfuly, how many services REALLY need admin access to the machine? A guide to posting questions on CodeProject[^] Dave Kreskowiak Microsoft MVP Visual Developer - Visual Basic      2006, 2007, 2008