CMake Error at .*/Modules/ExternalData.cmake:[0-9]+ \(message\): ExternalData_SERIES_PARSE is set to NotASeriesRegex which is not of the form \(<number>\)\(<suffix>\)\$ Fix the regular expression or set variables ExternalData_SERIES_PARSE_PREFIX = <prefix> regex group number, if any ExternalData_SERIES_PARSE_NUMBER = <number> regex group number ExternalData_SERIES_PARSE_SUFFIX = <suffix> regex group number Call Stack \(most recent call first\): .* BadSeries1.cmake:3 \(ExternalData_Expand_Arguments\) CMakeLists.txt:3 \(include\)