The SHUTDOWNDAYS msi property is for a REG_DWORD setting in the registry. This is different from the -shutdowndays command line switch. For the command line switch the days are specified as integers, where 0 = Sun, 1 = Mon, 2 = Tue etc. For the MSI property and the corresponding registry entry each of those integers corresponds to a binary value, where 0 (Sun) = 1, 1 (Mon) = 2, 2 (Tue) = 4, 3 (Wed) = 8, 4 (Thu) = 16, 5 (Fri) = 32, and 6 (Sat) = 64. To obtain the correct value you must add the binary values for each day specified, the default is 127 (every day). Monday-Friday which would be '-shutdowndays 1-5' on the command line is 62 (2+4+8+16+32) for the MSI Property and Registry entry.