diff --git a/packages/compass-preferences-model/src/global-config.spec.ts b/packages/compass-preferences-model/src/global-config.spec.ts
index 00511516ecb..63f41ea1200 100644
--- a/packages/compass-preferences-model/src/global-config.spec.ts
+++ b/packages/compass-preferences-model/src/global-config.spec.ts
@@ -130,7 +130,7 @@ forceConnectionOptions:
       globalConfigPaths: [],
       argv: ['--enable-maps=true', '--theme'],
     });
-    expect(result.cli).to.deep.equal({ enableMaps: true });
+    expect(result.cli).to.deep.equal({ enableMaps: true, theme: 'LIGHT' });
   });
 
   it('knows the expected types of cli options when followed by an extra positional argument', async function () {
@@ -226,4 +226,28 @@ forceConnectionOptions:
       'See the MongoDB Compass documentation for more details.'
     );
   });
+
+  it('allows empty theme option and defaults to LIGHT', async function () {
+    const result = await parseAndValidateGlobalPreferences({
+      globalConfigPaths: [],
+      argv: ['--theme='],
+    });
+    expect(result.cli).to.deep.equal({ theme: 'LIGHT' });
+  });
+
+  it('allows lowercase theme value', async function () {
+    const result = await parseAndValidateGlobalPreferences({
+      globalConfigPaths: [],
+      argv: ['--theme=dark'],
+    });
+    expect(result.cli).to.deep.equal({ theme: 'DARK' });
+  });
+
+  it('allows empty optional string value', async function () {
+    const result = await parseAndValidateGlobalPreferences({
+      globalConfigPaths: [],
+      argv: ['--username', '--password'],
+    });
+    expect(result.cli).to.deep.equal({ username: '', password: '' });
+  });
 });
diff --git a/packages/compass-preferences-model/src/preferences.ts b/packages/compass-preferences-model/src/preferences.ts
index 25ca750936c..1b5b5a4fb20 100644
--- a/packages/compass-preferences-model/src/preferences.ts
+++ b/packages/compass-preferences-model/src/preferences.ts
@@ -285,6 +285,8 @@ const storedUserPreferencesProps: Required<{
     },
     validator: Joi.string<THEMES>()
       .valid(...THEMES_VALUES)
+      .uppercase() // allow lowercase and convert it to uppercase
+      .empty('') // allow empty string and its defaulted to LIGHT
       .default('LIGHT'),
   },
   /**
@@ -639,7 +641,7 @@ const nonUserPreferences: Required<{
     description: {
       short: 'Specify a List of Connections for Automatically Connecting',
     },
-    validator: Joi.string().optional(),
+    validator: Joi.string().optional().allow(''),
   },
   username: {
     ui: false,
@@ -648,7 +650,7 @@ const nonUserPreferences: Required<{
     description: {
       short: 'Specify a Username for Automatically Connecting',
     },
-    validator: Joi.string().optional(),
+    validator: Joi.string().optional().allow(''),
   },
   password: {
     ui: false,
@@ -657,7 +659,7 @@ const nonUserPreferences: Required<{
     description: {
       short: 'Specify a Password for Automatically Connecting',
     },
-    validator: Joi.string().optional(),
+    validator: Joi.string().optional().allow(''),
   },
 };