eMake does not support UNC pathnames in eMake root values. Therefore, if
the user specifies a UNC path as an eMake root (either with the
--emake-root command-line option or the EMAKE_ROOT environment
variable), eMake will display this error and exit. The offending path is
given in the error message.
Remove the UNC path from the eMake root specification. If your build requires files from that UNC path, you can use the subst command to map the UNC path to a Windows drive letter, then specify that drive in the eMake root.
Note that some versions of eMake (5.2.x) incorrectly identify paths like “X:” as UNC paths (that is, a two-letter path consisting of a drive letter followed by a colon). Subsequent releases have corrected this error.