Hi, I've an basic MSI Project with a custom action scheduled in the UI Sequence. This action invokes a function of an C# Dll file stored in the binary table. Inside of this function I use MsiGetProperty to retrieve a path (basically the SourceDir which was copied into an own property before) of the msi package. This works fine as long as the MSI is installed from a directory with a short path e.g: "C:\Test\" If the path gets a bit longer (for example you copy the msi to the Windows Desktop, resulting in a path like "C:\Users\Administrator\Desktop\ProductName\Installx64\" -> so just about 50 Characters) the MsiGetProperty seems not to return the appropiate value anymore. At this point I can see in the MSILog my property was set before and contains the correct value - I just can't get it. The code I use looks like this: [CODE] [DllImport("msi.dll", CharSet = CharSet.Ansi)] private static extern int MsiGetProperty(IntPtr hInstall, string szName, [Out] StringBuilder szValueBuf, ref int pchValueBuf); private static String GetPropertyStringValue(IntPtr hInstall, String PropertyName) { try { int BufferSize = 0; int GetResult = 0; StringBuilder sb = new StringBuilder(); GetResult = MsiGetProperty(hInstall, PropertyName, sb, ref BufferSize); if (ERROR_MORE_DATA == GetResult) { var sb2 = new StringBuilder(); int FullSize = BufferSize + 1; GetResult = MsiGetProperty(hInstall, PropertyName, sb2, ref FullSize); sb = sb2; } return sb.ToString(); } catch (Exception ex) { MsiSetProperty(hInstall, "ERRORMESSAGE", String.Format("{0}: {1}", PropertyName, "failed with ex")); MsiSetProperty(hInstall, "ERRORMESSAGE", String.Format("{0}: {1}", PropertyName, ex.ToString())); } return string.Empty; }[/CODE] I tried a lot of things right now: Using other charset, adding 2, 10, 20 instewaad of just 1 to the buffersize to ensure it is big enough. I added some kind of "debug.Prints" into my ERRORMESSAGE property to check in the Msi Log if my function is called, check the returned Buffersize and so on. I seems like any code below the 2nd call of MsiGetProperty is not executed (obviously I would expect an exception message in case of a runtime error), therefore I can't tell what's the returned result-value of that Api call. The strange thing is this works fine until the property value is shorter than ~30 Characters. Does anybody have an idea what I'm doing wrong or new to add here? ... View more