diff --git a/include/europa/io/PakWriter.hpp b/include/europa/io/PakWriter.hpp
index 07955d3..75a57bb 100644
--- a/include/europa/io/PakWriter.hpp
+++ b/include/europa/io/PakWriter.hpp
@@ -41,7 +41,7 @@ namespace europa::io {
 		/// Write archive to the given output stream.
 		/// [vec] is all files which should be packaged
 		/// [sink] is a implementation of PakProgressReportsSink which should get events (TODO: Make this optional)
-		/// [sectorAlignment] controls sector alignment
+		/// [sectorAlignment] controls sector alignment. It is ignored unless the package's version is [structs::PakVersion::Ver5].
 		void Write(std::ostream& os, std::vector<FlattenedType>&& vec, PakProgressReportSink& sink, SectorAlignment sectorAlignment = SectorAlignment::DoNotAlign);
 
 	   private:
diff --git a/src/tools/eupak/main.cpp b/src/tools/eupak/main.cpp
index 9a36aba..5686645 100644
--- a/src/tools/eupak/main.cpp
+++ b/src/tools/eupak/main.cpp
@@ -12,6 +12,8 @@
 #include <tasks/ExtractTask.hpp>
 #include <tasks/InfoTask.hpp>
 
+#include "europa/structs/Pak.hpp"
+
 int main(int argc, char** argv) {
 	// FIXME: At some point we should just have task classes register their arguments
 	// and then they will deal with all that themselves. The only thing we will do here
@@ -162,6 +164,12 @@ int main(int argc, char** argv) {
 
 		args.sectorAligned = createParser.get<bool>("--sector-aligned");
 
+		if(args.sectorAligned && args.pakVersion != eupak::estructs::PakVersion::Ver5) {
+			std::cout << "Error: --sector-aligned is only valid for creating a package with \"-V jedistarfighter\".\n"
+					  << createParser;
+			return 1;
+		}
+
 		if(!eupak::fs::is_directory(args.inputDirectory)) {
 			std::cout << "Error: Provided input isn't a directory\n"
 					  << createParser;