diff --git a/omega-pac/src/profiles.coffee b/omega-pac/src/profiles.coffee
index c74da02..3a68270 100644
--- a/omega-pac/src/profiles.coffee
+++ b/omega-pac/src/profiles.coffee
@@ -311,8 +311,17 @@ module.exports = exports =
           new U2.AST_Dot property: 'call', expression: new U2.AST_Function(
             argnames: []
             body: [
+              # https://github.com/FelisCatus/SwitchyOmega/issues/390
+              # 1. Add \n after PAC to terminate line comment in PAC (// ...)
+              # 2. Add another \n with knowledge that the first can be escaped
+              #    by trailing backslash in PAC. (// ... \)
+              # 3. Add a multiline-comment block /* ... */ to terminate any
+              #    potential unclosed multiline-comment block. (/* ...)
+              # 4. And finally, a semicolon to terminate the final statement.
+              # Wait a moment. Do we really need to go this far? I don't know.
+
               # TODO(catus): Remove the hack needed to insert raw code.
-              new AST_Raw ';\n' + profile.pacScript + ';'
+              new AST_Raw ';\n' + profile.pacScript + '\n\n/* End of PAC */;'
               new U2.AST_Return value:
                 new U2.AST_SymbolRef name: 'FindProxyForURL'
             ]
diff --git a/omega-pac/test/profiles.coffee b/omega-pac/test/profiles.coffee
index 59c2c2a..5094fae 100644
--- a/omega-pac/test/profiles.coffee
+++ b/omega-pac/test/profiles.coffee
@@ -98,7 +98,7 @@ describe 'Profiles', ->
         host: '127.0.0.1'
         port: 1234
       fallbackProxy:
-        scheme: 'socks5'
+        scheme: 'socks4'
         host: '127.0.0.1'
         port: 1234
     it 'should use protocol-specific proxies if suitable', ->
@@ -106,7 +106,7 @@ describe 'Profiles', ->
         ['PROXY 127.0.0.1:1234', 'https'])
     it 'should use fallback proxies for other protocols', ->
       testProfile(profile, 'ftp://www.example.com/',
-        ['SOCKS5 127.0.0.1:1234', ''])
+        ['SOCKS 127.0.0.1:1234', ''])
     it 'should not use any proxy for requests matching the bypassList', ->
       testProfile profile, 'ftp://localhost/', ['DIRECT', profile.bypassList[0]]
   describe 'PacProfile', ->
@@ -119,12 +119,25 @@ describe 'Profiles', ->
     it 'should return the result of the pac script', ->
       testProfile(profile, 'ftp://www.example.com:9999/abc', null,
         'PROXY www.example.com:8080')
+    it 'should not fail for PAC with trailing comments', ->
+      p = Profiles.create('test', 'PacProfile')
+      p.pacScript = profile.pacScript + '''
+        // This is a trailing line comment.
+      '''
+      testProfile(p, 'ftp://www.example.com:9999/abc', null,
+        'PROXY www.example.com:8080')
+      p = Profiles.create('test', 'PacProfile')
+      p.pacScript = profile.pacScript + '''
+        /* This is a multiline comment which is not properly closed.
+      '''
+      testProfile(p, 'ftp://www.example.com:9999/abc', null,
+        'PROXY www.example.com:8080')
     it 'should return includable for non-file pacUrl', ->
       Profiles.isIncludable(profile).should.be.true
     it 'should return not includable for file: pacUrl', ->
-      profile = Profiles.create('test', 'PacProfile')
-      profile.pacUrl = 'file:///proxy.pac'
-      Profiles.isIncludable(profile).should.be.false
+      p = Profiles.create('test', 'PacProfile')
+      p.pacUrl = 'file:///proxy.pac'
+      Profiles.isIncludable(p).should.be.false
   describe 'SwitchProfile', ->
     profile = Profiles.create('test', 'SwitchProfile')
     profile.rules = [