BLD:U0013
MSI requires separator character for append or remove
The indicated object specifies an append or prepend installation action, but the separator character is empty. MSI cannot handle empty separator characters with append or prepend; instead, it will use the first or last character of the actual value as the separator character. This will probably cause problems.
Solution
Make sure that you specify a suitable separator character if you request append or prepend and are building an MSI installer. Alternatively, build an InstallMate installer instead.
See also
Environment Variables
InstallMate versus Windows Installer