diff --git a/src/modules/argumentsParser.ts b/src/modules/argumentsParser.ts
index 9cde7ea1a..ddd720be0 100644
--- a/src/modules/argumentsParser.ts
+++ b/src/modules/argumentsParser.ts
@@ -353,7 +353,7 @@ export default class ArgumentsParser {
           .map((mode) => mode.toLowerCase()),
         coerce: ArgumentsParser.getLastValue, // don't allow string[] values
         requiresArg: true,
-        default: MergeMode[MergeMode.NONMERGED].toLowerCase(),
+        default: MergeMode[MergeMode.FULLNONMERGED].toLowerCase(),
       })
 
       .option('filter-regex', {
diff --git a/test/modules/argumentsParser.test.ts b/test/modules/argumentsParser.test.ts
index 3e3156f62..d9d4e0652 100644
--- a/test/modules/argumentsParser.test.ts
+++ b/test/modules/argumentsParser.test.ts
@@ -109,7 +109,7 @@ describe('options', () => {
 
     expect(options.getSymlinkRelative()).toEqual(false);
 
-    expect(options.getMergeRoms()).toEqual(MergeMode.NONMERGED);
+    expect(options.getMergeRoms()).toEqual(MergeMode.FULLNONMERGED);
 
     expect(options.getFilterRegex()).toBeUndefined();
     expect(options.getFilterRegexExclude()).toBeUndefined();
@@ -516,7 +516,7 @@ describe('options', () => {
 
   it('should parse "merge-roms"', () => {
     expect(argumentsParser.parse(dummyCommandAndRequiredArgs).getMergeRoms())
-      .toEqual(MergeMode.NONMERGED);
+      .toEqual(MergeMode.FULLNONMERGED);
     expect(() => argumentsParser.parse([...dummyCommandAndRequiredArgs, '--merge-roms', 'foobar']).getMergeRoms()).toThrow(/invalid values/i);
     expect(argumentsParser.parse([...dummyCommandAndRequiredArgs, '--merge-roms', 'fullnonmerged']).getMergeRoms()).toEqual(MergeMode.FULLNONMERGED);
     expect(argumentsParser.parse([...dummyCommandAndRequiredArgs, '--merge-roms', 'nonmerged']).getMergeRoms()).toEqual(MergeMode.NONMERGED);