diff --git a/app/soapbox/normalizers/soapbox/__tests__/soapbox-config.test.ts b/app/soapbox/normalizers/soapbox/__tests__/soapbox-config.test.ts
index 5eccab870..6901254f2 100644
--- a/app/soapbox/normalizers/soapbox/__tests__/soapbox-config.test.ts
+++ b/app/soapbox/normalizers/soapbox/__tests__/soapbox-config.test.ts
@@ -37,6 +37,7 @@ describe('normalizeSoapboxConfig()', () => {
 
   it('upgrades singleUserModeProfile to redirectRootNoLogin', () => {
     expect(normalizeSoapboxConfig({ singleUserMode: true, singleUserModeProfile: 'alex' }).redirectRootNoLogin).toBe('/@alex');
+    expect(normalizeSoapboxConfig({ singleUserMode: true, singleUserModeProfile: '@alex' }).redirectRootNoLogin).toBe('/@alex');
     expect(normalizeSoapboxConfig({ singleUserMode: false, singleUserModeProfile: 'alex' }).redirectRootNoLogin).toBe('');
   });
 
diff --git a/app/soapbox/normalizers/soapbox/soapbox-config.ts b/app/soapbox/normalizers/soapbox/soapbox-config.ts
index f2366bdf1..eba76454c 100644
--- a/app/soapbox/normalizers/soapbox/soapbox-config.ts
+++ b/app/soapbox/normalizers/soapbox/soapbox-config.ts
@@ -198,13 +198,13 @@ const normalizeAdsAlgorithm = (soapboxConfig: SoapboxConfigMap): SoapboxConfigMa
 
 /** Single user mode is now managed by `redirectRootNoLogin`. */
 const upgradeSingleUserMode = (soapboxConfig: SoapboxConfigMap): SoapboxConfigMap => {
-  const singleUserMode = soapboxConfig.get('singleUserMode');
-  const singleUserModeProfile = soapboxConfig.get('singleUserModeProfile');
-  const redirectRootNoLogin = soapboxConfig.get('redirectRootNoLogin');
+  const singleUserMode = soapboxConfig.get('singleUserMode') as boolean | undefined;
+  const singleUserModeProfile = soapboxConfig.get('singleUserModeProfile') as string | undefined;
+  const redirectRootNoLogin = soapboxConfig.get('redirectRootNoLogin') as string | undefined;
 
   if (!redirectRootNoLogin && singleUserMode && singleUserModeProfile) {
     return soapboxConfig
-      .set('redirectRootNoLogin', `/@${singleUserModeProfile}`)
+      .set('redirectRootNoLogin', `/@${singleUserModeProfile.replaceAll('@', '')}`)
       .deleteAll(['singleUserMode', 'singleUserModeProfile']);
   } else {
     return soapboxConfig