diff --git a/plugins/FilePack/FilePackPlugin.py b/plugins/FilePack/FilePackPlugin.py
index 29cd7390..7ba6b452 100644
--- a/plugins/FilePack/FilePackPlugin.py
+++ b/plugins/FilePack/FilePackPlugin.py
@@ -47,7 +47,7 @@ class UiRequestPlugin(object):
             if not os.path.isfile(archive_path):
                 site = self.server.site_manager.get(path_parts["address"])
                 if not site:
-                    self.error404(path)
+                    return self.actionSiteAddPrompt(path)
                 # Wait until file downloads
                 result = site.needFile(site.storage.getInnerPath(archive_path), priority=10)
                 # Send virutal file path download finished event to remove loading screen
diff --git a/src/Ui/UiRequest.py b/src/Ui/UiRequest.py
index d555d7ee..91ca261b 100644
--- a/src/Ui/UiRequest.py
+++ b/src/Ui/UiRequest.py
@@ -102,6 +102,9 @@ class UiRequest(object):
         # Wrapper-less static files
         elif path.startswith("/raw/"):
             return self.actionSiteMedia(path.replace("/raw", "/media", 1), header_noscript=True)
+
+        elif path.startswith("/add/"):
+            return self.actionSiteAdd()
         # Site media wrapper
         else:
             if self.get.get("wrapper_nonce"):
@@ -194,7 +197,7 @@ class UiRequest(object):
            headers.append(("Access-Control-Allow-Origin", "*"))  # Allow load font files from css
 
         if noscript:
-            headers.append(("Content-Security-Policy", "default-src 'none'; sandbox allow-top-navigation; img-src 'self'; font-src 'self'; media-src 'self'; style-src 'self' 'unsafe-inline';"))
+            headers.append(("Content-Security-Policy", "default-src 'none'; sandbox allow-top-navigation allow-forms; img-src 'self'; font-src 'self'; media-src 'self'; style-src 'self' 'unsafe-inline';"))
 
         if self.env["REQUEST_METHOD"] == "OPTIONS":
             # Allow json access
@@ -382,6 +385,12 @@ class UiRequest(object):
         self.server.wrapper_nonces.append(wrapper_nonce)
         return wrapper_nonce
 
+    # Create a new wrapper nonce that allows to get one site
+    def getAddNonce(self):
+        add_nonce = CryptHash.random()
+        self.server.add_nonces.append(add_nonce)
+        return add_nonce
+
     def isSameOrigin(self, url_a, url_b):
         if not url_a or not url_b:
             return False
@@ -448,7 +457,7 @@ class UiRequest(object):
                     return self.actionRedirect("./%s/" % path_parts["address"])
             else:  # File not exists, try to download
                 if address not in SiteManager.site_manager.sites:  # Only in case if site already started downloading
-                    return self.error404(path_parts["inner_path"])
+                    return self.actionSiteAddPrompt(path)
 
                 site = SiteManager.site_manager.need(address)
 
@@ -486,6 +495,26 @@ class UiRequest(object):
         else:  # Bad url
             return self.error400()
 
+    def actionSiteAdd(self):
+        post = dict(cgi.parse_qsl(self.env["wsgi.input"].read()))
+        if post["add_nonce"] not in self.server.add_nonces:
+            return self.error403("Add nonce error.")
+        self.server.add_nonces.remove(post["add_nonce"])
+        SiteManager.site_manager.need(post["address"])
+        return self.actionRedirect(post["url"])
+
+    def actionSiteAddPrompt(self, path):
+        path_parts = self.parsePath(path)
+        if not path_parts or not self.server.site_manager.isAddress(path_parts["address"]):
+            return self.error404(path)
+
+        self.sendHeader(200, "text/html", noscript=True)
+        template = open("src/Ui/template/site_add.html").read()
+        template = template.replace("{url}", cgi.escape(self.env["PATH_INFO"], True))
+        template = template.replace("{address}", path_parts["address"])
+        template = template.replace("{add_nonce}", self.getAddNonce())
+        return template
+
     # Stream a file to client
     def actionFile(self, file_path, block_size=64 * 1024, send_header=True, header_length=True, header_noscript=False):
         if ".." in file_path:
diff --git a/src/Ui/UiServer.py b/src/Ui/UiServer.py
index d623c2c3..926f1fea 100644
--- a/src/Ui/UiServer.py
+++ b/src/Ui/UiServer.py
@@ -69,6 +69,7 @@ class UiServer:
             self.learn_allowed_host = True  # It will pin to the first http request's host
 
         self.wrapper_nonces = []
+        self.add_nonces = []
         self.site_manager = SiteManager.site_manager
         self.sites = SiteManager.site_manager.list()
         self.log = logging.getLogger(__name__)
diff --git a/src/Ui/template/site_add.html b/src/Ui/template/site_add.html
new file mode 100644
index 00000000..29481868
--- /dev/null
+++ b/src/Ui/template/site_add.html
@@ -0,0 +1,40 @@
+<html>
+<head>
+<title>Add new site</title>
+</head>
+<body>
+
+<style>
+.content { line-height: 24px; font-family: monospace; font-size: 14px; color: #636363; text-transform: uppercase; top: 38%; position: relative; text-align: center; }
+.content h1, .content h2 { font-weight: normal; letter-spacing: 1px; }
+.content h2 { font-size: 15px; margin-bottom: 50px }
+.content #details {
+    text-align: left; display: inline-block; width: 350px; background-color: white; padding: 17px 27px; border-radius: 0px;
+    box-shadow: 0px 2px 7px -1px #d8d8d8; text-transform: none; margin: 15px; transform: scale(0) rotateX(90deg); transition: all 0.6s cubic-bezier(0.785, 0.135, 0.15, 0.86);
+}
+.content #details #added { font-size: 12px; text-align: right; color: #a9a9a9; }
+
+.button {
+    padding: 8px 20px; background-color: #FFF85F; border-bottom: 2px solid #CDBD1E; border-radius: 2px;
+    text-decoration: none; transition: all 0.5s; background-position: left center; color: black;
+    border-left: 0px; border-top: 0px; border-right: 0px; font-family: monospace; font-size: 14px;
+}
+.button:hover { background-color: #FFF400; border-bottom: 2px solid #4D4D4C; transition: none; }
+.button:active { position: relative; top: 1px; }
+.button:focus { outline: none; }
+
+</style>
+
+<div class="content">
+ <h1>Add new site</h1>
+ <h2>Please confirm before add new site to the client</h2>
+ <form action="/add/" method="POST">
+  <input type="hidden" name="add_nonce" value="{add_nonce}">
+  <input type="hidden" name="address" value="{address}">
+  <input type="hidden" name="url" value="{url}">
+  <input type="submit" class="button button-submit" id="button" value="Load site"/>
+ </form>
+</div>
+
+</body>
+</html>
\ No newline at end of file